In the most devastating terrorist attack in Spanish history, 10 bombs detonating minutes apart ripped through crowded commuter trains at three Madrid stations early Thursday, killing nearly 200 people, injuring 1,400 and sending this capital into convulsions of shock and horror three days before a national election.
Authorities immediately blamed the Basque separatist group ETA for the deadliest act of terrorism seen in Europe in almost two decades. But the scale of carnage went far beyond anything the separatists had ever carried out and led to speculation that other groups might be responsible.
Interior Minister Angel Acebes initially said it was "absolutely clear" that ETA was responsible. Late Thursday, however, he went before reporters to say police had recovered a stolen van with seven bomb detonators and a tape recording of Koranic verses read in Arabic. The van was found in a suburb where the targeted trains originated, he said.
"I have instructed security forces not to discard any line of investigation," Acebes said.
A short time later, an Arabic-language newspaper in London said it had received a letter claiming responsibility for the bombings in the name of Al Qaeda, having "infiltrated the heart of Europe."
The rush-hour blasts paralyzed Madrid. Political parties canceled what remained of their election campaigns, the right-wing government of Prime Minster Jose Maria Aznar declared three days of mourning, and frantic relatives searched for loved ones at morgues and hospitals.
"This is mass murder," an ashen Aznar said after an emergency Cabinet meeting. "The date of March 11 now holds its place in infamy."
A hellish scene of destruction and anguish repeated itself at the three stations, including Atocha, the largest in Madrid and a hub for subways and long-distance trains just south of the famed Prado Museum.
About 7:40 a.m., three bombs shattered a commuter train that had just pulled into Atocha. Minutes later, four explosions ravaged a train a short distance away. Another bomb exploded at the Santa Eugenia station, four stops away, followed by two bombs in a train at the El Pozo station, two stops from Atocha. The three stations anchor a nine-mile stretch of commuter railway into Madrid.
The Interior Ministry said the explosives and detonation devices in all 10 bombs -- crammed into backpacks and bags left on the targeted trains or on station platforms -- resembled those used by ETA in its attacks.
Throughout the morning and into the afternoon, rescue workers pulled bodies and pieces of bodies from the shells of passenger cars that had been packed with workaday Spaniards, students and immigrants.
At Atocha, the dead and dying lay alongside the tracks or in a makeshift triage center, covered by blankets and attended by frantic medics. Burned and bloody survivors staggered from the wreckage.
"There was blood everywhere," said Angel Grandes, 39, who was waiting for the train at Atocha. "There was a 20-year-old boy, who came out all torn up. He came near me, I grabbed his arm and he fell. He died right there, at my feet."
Sobbing as he recounted the scene, Grandes repeated over and over: "So much blood, so much blood. And so many blankets, all covering the bodies. It was Dantesque."
"The train was cut open like a can of tuna," Enrique Sanchez, one of a legion of overwhelmed ambulance drivers, told reporters. "One carriage [was] totally blown apart. People were scattered all over the platforms. I saw legs and arms. I won't forget this ever."
Rather than climb steadily, the death toll seemed to leap.
By nightfall, authorities had counted 192 dead, and many of the injured were in critical condition. Several children and pregnant women were among those killed, Spanish television reported. Identification was difficult because of the condition of the bodies, a coroner's official said.
There were conflicting theories about who carried out the attacks.
A shadowy Islamic extremist group, the Abu Hafs al-Masri Brigades, claimed responsibility, for striking at "the heart of the crusade," according to the letter received by the newspaper Al-Quds Al-Arabi. The same group had faxed a letter to the paper to claim responsibility for deadly suicide bombings in Istanbul in November.
The United States believes that the group, which is named for a high-ranking Al Qaeda member, lacks credibility and that its ties to the network are tenuous. In the past, the group has made claims about events to which it wasn't connected, such as blackouts last year in the U.S., Canada and Britain.
The Spanish government was a staunch supporter of the Bush administration's war in Iraq and has sent troops to the country. A number of alleged supporters of Al Qaeda-style terrorist groups have been arrested in Spain.
Acebes, the interior minister, said all avenues of investigation would be examined, but he said he continued to believe that the main suspect was ETA.
Normally, ETA owns up to its attacks. An outlawed political wing of the group denied ETA involvement and sought to shift the blame to Islamic militants. But many Basque political leaders joined their Spanish counterparts in blaming ETA and in condemning the bloodshed.
"ETA writes its own epitaph with this," said Juan Jose Ibarretxe, head of the autonomous Basque government.
The targeting of civilians for wholesale slaughter is out of character with most of the attacks carried out by ETA guerrillas in more than 30 years of fighting for secession from Spain.
But the militants -- many of their leaders jailed and support for the organization flagging -- reportedly have been seeking a high-profile, dramatic way to reassert themselves.
Analysts suggest that younger, less politically astute ETA fighters -- perhaps having seen the impact of large-scale terrorism by Al Qaeda and others -- may be more inclined to launch the kind of attacks that occurred here Thursday.
"Maybe this was more than they bargained for, but it was clearly a way to insist they still exist and say, 'We are not dead,' " Gorka Espiau, a Basque human rights activist, said from San Sebastian. "For a while, they have been attempting to pull off something big."
Thirteen bombs were planted in trains and stations, Interior Ministry officials said. The three that failed to explode were disposed of by police. Each contained about 33 pounds of a type of dynamite used by ETA, the officials said.
Suspected ETA members were intercepted by authorities last month as they headed for Madrid with 1,000 pounds of explosives, the ministry said. Police foiled a plot to blow up a train in Madrid on Christmas Eve, a scheme also attributed to ETA.
"ETA had been looking for a massacre in Spain," Acebes said.
Despite the suspension of election campaigning, Aznar said Sunday's vote would be held as scheduled. He is not seeking reelection, but his Popular Party has been leading in the polls and is expected to win easily.
Aznar has adopted an especially hard line against Basque separatists and has refused to negotiate with them -- a stance he reiterated Thursday. His party has used the campaign to essentially declare victory over ETA, which wants a Basque state carved from lush northern Spain and southern France.
For 25 years, after the death of Spanish dictator Gen. Francisco Franco, Basques have enjoyed considerable autonomy, including their own regional parliament and police force. Though many Basques want more, most oppose the harsh tactics of ETA.
Spain is no stranger to political violence, having lived through a civil war in the 1930s, a long fascist dictatorship and three decades of separatism. But Thursday was different. Dazed citizens struggled to come to terms with what had happened.
The death toll was the highest from a terrorist attack in Europe since December 1988, when a bomb exploded on a Pan American jet over Scotland, killing 270 people.
"Our 9/11," read the headline of one of numerous newspapers that published extra editions Thursday. All television stations showed a logo of a black ribbon, and flags went to half-staff.
Demonstrations sprang up around the country, with minutes of silence and demands for peace, an end to violence and severe punishment for the culprits. So many people heeded an urgent call to give blood that they had to be turned away.
King Juan Carlos I addressed the nation, declaring that "an act of barbaric terrorism has engulfed Spain with profound pain, repulsion and anger."
International condemnation and solidarity were swift. President Bush telephoned the king and Aznar. In Washington he said, "We weep with the families."
British Prime Minister Tony Blair said that "these people will not disrupt our democracy," and he repudiated what he called an "unspeakable evil."
Special correspondent Cristina Mateo-Yanguas contributed to this report.