Two truck bombs exploded outside the British Consulate and the headquarters of the London-based HSBC bank in Istanbul on Thursday morning, killing at least 27 people, injuring more than 500 and spreading fear across a city already reeling from similar attacks five days earlier.
Turkish and British officials immediately blamed the suicide attacks on Islamic extremists and said the devastating blasts bore the trademarks of Al Qaeda and the organizations that fall under its terrorist umbrella.
Aimed at British interests, the attacks coincided with President Bush's state visit to Britain, where he defended the U.S.-led invasion of Iraq.
"It shows how important it is to carry on until terrorism is defeated," British Prime Minister Tony Blair said at a news conference. "And I can assure you of one thing -- that when something like this happens today, our response is not to flinch or give way or concede one inch. We stand absolutely firm until this job is done -- done in Iraq, done elsewhere in the world."
Bush agreed. "Great Britain, America and other free nations are united today in our grief and united in our determination to fight and defeat this evil, wherever it is found," Bush said.
A member of the North Atlantic Treaty Organization and aspirant to the European Union, Turkey may have been targeted because the predominantly Muslim country has a secular, moderate government. It is also a close ally of the United States and Israel. On Saturday, two Istanbul synagogues were attacked. Twenty-five people died, including the two suicide bombers.
Turkey has continued to voice support for the U.S.-led war in Iraq and the war on terrorism and was one of the few countries to offer troops for Iraq, although the proposal was scuttled when Iraqis objected to the presence of Turkish soldiers.
The government, led by an Islamist party, will be under great pressure to arrest Islamic militants to prove itself to U.S. and international partners as well as to Turkey's restive secular military. Turkish Prime Minister Recep Tayyip Erdogan immediately vowed a broadened crackdown, saying, "Turkey will be like a fist."
Officials were quick to point to the Al Qaeda network, saying the tactics were similar to past attacks.
"It has all the hallmarks of the international terror practices by Al Qaeda and associated organizations," Jack Straw, the British foreign secretary, said in London before leaving for Turkey, where he visited the ravaged consulate Thursday.
The massive blast at the consulate leveled the security checkpoint and a cafeteria within the stately complex in Beyoglu, one of the city's busiest pedestrian districts and a popular neighborhood for foreign tourists.
Chunks of debris and shards of glass rained over 10 square blocks, inundating area hospitals with victims. At least 14 people were killed in that attack, including Roger Short, the British consul general, and three Turkish policemen.
At the HSBC headquarters five miles north, the glass facade was blown off the 18-story building and flying glass injured dozens in the bustling Levent business district, while several cars were engulfed in flames.
At least 13 people were believed killed there, including employees of the bank.
As with Saturday's attacks, most of the victims Thursday were Turkish Muslims.
Terrorism experts said they were surprised that two well-coordinated attacks could be launched so soon after those on Saturday. But some experts also said Turkey had a ready supply of Islamic extremists.
"There are hundreds of Turks who went to Afghanistan, Iran and Pakistan for training, who fought in Chechnya, and no one was really paying attention to them," said Hasan Koni, an advisor to Turkey's National Security Council and a political scientist at Ankara University.
A senior Turkish security official, speaking on condition of anonymity, said authorities were extremely worried that the bombings were the start of a sustained campaign to destabilize the country. He warned that U.S. targets could be next.
"We may expect an attack in Ankara, Istanbul or any American target in Turkey," he said.
The U.S. Consulate warned its citizens Thursday that more attacks were possible and advised them to stay away from shopping centers and Western businesses.
Initial reports from Turkish security officials said the explosives were concealed in two trucks and were detonated as the vehicles were driven past the consulate and the bank building, both of which are in congested areas where traffic moves slowly.
Standing in front of Taksim hospital near the consulate, amid grieving relatives and grim-faced rescue workers, Turkish Interior Minister Abdulkadir Aksu said the attacks were similar to the synagogue explosions.
"Pickups loaded with explosives were driven by suicide attackers," he said.
Authorities said initial forensic tests indicated the same type of explosives was used Thursday and Saturday. However, they said the bombs used Thursday were larger and the devastation more widespread.
The air outside the bank smelled heavily of fuel oil, an ingredient used to bind the ammonium sulfate and nitrate in the homemade bomb.
The explosions echoed for miles across the many hills of Istanbul and even on the Asian side of the Bosporus, sparking fears that an earthquake had struck before television and radio broadcasts were interrupted with news of attacks for the second time in five days.
A caller to Turkey's semiofficial Anatolian news agency claimed responsibility in the name of a Turkish group, the Great Eastern Islamic Raiders' Front, that authorities say is linked to Osama bin Laden's Al Qaeda network. The same little-known Turkish group claimed responsibility for the synagogue attacks.
Turkish police had identified the bodies of the two suicide bombers in Saturday's attacks and said they were Turkish men who belonged to militant groups loosely affiliated with Al Qaeda. Authorities said that the men had trained outside Turkey and that one had fought alongside Islamic rebels in Chechnya.
Turkish police detained about 30 people for questioning after the synagogue blasts and quickly identified the suicide bombers and two of their alleged accomplices. There were not, however, the arrests of hundreds that were made in Saudi Arabia and Morocco following recent terrorist bombings.
"We have solved the case of Saturday very quickly," said Aksu, the interior minister. "These attacks will also be solved."
The first blast Thursday occurred shortly before 11 a.m. as a line of vehicles passed the HSBC building. Water gushed from broken pipes on the upper floors, and the blast dug a crater 9 feet deep in front of the building.
Across the wide boulevard, about 150 feet from the site of the blast, windows were blown out up to the 28th floor of a popular shopping mall.
A few yards from the bank building, a small car sat smoldering, its four doors blown open and windows shattered. Nearby, Murat Aysel stood in the middle of the street, appearing dazed as blood streamed from cuts on his face.
"I was working in the kitchen, and when I heard the explosion I thought it was the gas tank," said Aysel, a cook at a restaurant in the HSBC building. "So I ran out onto the street. I saw so many cars, maybe 10 or 15 on the street, burning. And I could see bodies in the cars, the street -- everywhere, it seemed."
Less than five minutes later, the second blast occurred in front of the security entrance to the consulate, which is set amid narrow streets of 19th century brick-and-stone buildings in a crowded neighborhood filled with shops and restaurants.
A policeman at the scene said that witnesses reported seeing a green van with the markings of a food company drive into the security gate at the consulate and then explode.
"I heard a large bang that I thought was an earthquake," Adnan Akyildiz, a cleaner at the consulate, told the Reuters news agency. "I threw myself out of the window.... The scene was horrendous. The gate, the consulate, the buildings were all demolished."
The main consulate building was undergoing renovation so many employees had been moved to temporary space along the periphery and within range of the blast. Short, 58, was reported to have been in the cafeteria near the security entrance.
From a nearby rooftop, a scene of devastation was evident inside the high walls surrounding the consulate complex. The security entrance and cafeteria were reduced to a pile of debris 6 feet high. A bulldozer was making its way through the rubble.
Until July, the U.S. Consulate was located about 300 yards from its British counterpart in a similarly grand old structure. But the Americans moved to a new, fortress-like building on a barren patch of hillside, half an hour's drive north of the Beyoglu neighborhood.
The 22-member Arab League condemned the attacks, along with the United Nations Security Council, which urged all nations to help bring the perpetrators to justice.
U.N. Secretary-General Kofi Annan said that the increasing threats would complicate the world organization's work around the region and that the U.N. is improving security for its staff -- all of whom have been withdrawn from Baghdad.
"I think everyone understands that we live in a rather dangerous world and a difficult world. We have seen bombs and attacks go on all around us, and we have also seen the U.N. itself and the blue flag targeted directly."
But few diplomats thought that the attacks would persuade nations to provide more troops or support to the U.S.-led effort in Iraq. Recent attacks on aid groups, Italian police and Spanish diplomats in Iraq already have demonstrated that backing the reconstruction effort carries great risks.
The bombs in Istanbul reinforced that message and alerted potential supporters that their interests would be vulnerable outside Iraq as well.
"We understand that it is urgent to stabilize the situation in Iraq, but I don't think anyone wants to jump in right now," said the French ambassador to the U.N., Jean-Marc de la Sabliere. "It showed that we now have to worry about being attacked outside of Iraq too."
Others did not view the attacks as directly related to the occupation. "It has nothing to do with Iraq," said Syrian Ambassador Fayssal Mekdad, whose country also condemned the bombings. "These attacks are directed at Turkey."
The latest attacks raised fears that Turkey's economic recovery could be stalled. The country faces large debt repayments next year and had been counting on foreign investment and improving tourism to boost revenue.
The Istanbul stock exchange was closed within minutes of the bombings, and the lira dropped sharply on foreign markets. Businessmen expressed fears that the repercussions of the blasts would be felt across the economy of this country of nearly 70 million people.
On Wednesday, Israel's Foreign Ministry had dropped a travel advisory against visiting Turkey that was imposed after the synagogue bombings. A flight to Istanbul was on the runway at Tel Aviv's Ben-Gurion International Airport after the latest blasts when passengers were given the chance to get off. Fifty of them, about a third of those on the flight, did so.
For Turkish citizens, government officials and independent experts, the question was why such attacks occurred in Turkey.
Some said the aim was to destabilize Turkey because of its position as a moderate Islamic democracy, NATO member and ally of the United States.
"In this vast geography, the greater Middle East, there is only one Muslim country that is semi-decent, stable, functional," said Solih Ozel, a political scientist at Istanbul's Bilgi University. "Turkey is the opposite of everything that Al Qaeda or any of its ilk stands for."
Other experts criticized Turkey for not doing enough to confront Islamic extremists operating on its soil. Last year, police arrested several suspected Al Qaeda operatives in southeastern Turkey. A second group was arrested with fake passports near Istanbul's Covered Bazaar. But some experts said the police did not follow up properly.
"It's clear that there's a huge vulnerability in the intelligence service in this country," said a senior intelligence source in Ankara. "These groups like Al Qaeda have many supporters in this country. Their numbers have been swelling as a result of U.S. policies in the wake of Sept. 11."
But in a sprawling and diverse city of as many as 15 million residents, protecting so-called soft targets from determined suicide bombers is very difficult, said intelligence analysts and diplomats.
"There is very little you can do to prevent these attacks," said a European diplomat in Istanbul. "The real issue is to find out who planned them. More serious attention must be devoted to local terrorist groups."
Frantz is a Times staff writer and Zaman is a special correspondent. Staff writers Laura King in Jerusalem, Tracy Wilkinson in Rome, Edwin Chen in London and Maggie Farley at the United Nations contributed to this report.