When Syria deployed thousands of soldiers along its frontier with northern Lebanon this month, some here feared that the Syrians were preparing to retake a country their military had dominated until it was pushed out in 2005.
But now, after a bombing Saturday that was the deadliest in Syria since 1986, analysts are wondering whether the troops were defensive, meant to stop an imminent attack from Lebanon-based Sunni Muslim militants inspired by Al Qaeda and sometimes trained in Iraq.
"The handwriting has been on the wall for a while," Sami Moubayed, a political analyst in Damascus, the Syrian capital, said Sunday. "There have been signs of trouble coming in from Iraq or Lebanon."
The car bombing killed 17 people and injured 14 in a crowded residential neighborhood on the outskirts of Damascus. The area is near an intelligence office and along the route to an important Shiite Muslim shrine.
It came as Syria performs delicate balancing acts in navigating the region's sectarian and political fault lines.
The Syrians have held peace talks with Israel while strengthening ties to Iran, the Jewish state's greatest enemy. They are trying to improve relations with the West and maintain what some describe as heavy influence in Lebanon, contrary to the demands of the United States and France.
Recently, Syria's Shiite-dominated allies in Lebanon won several political victories, angering Sunni militants who consider the secular government of Syrian President Bashar Assad an enemy.
Northern Lebanon has long been a bastion for Sunni radicals, some of them veterans of the Iraq insurgency. Fatah al Islam, a group with Al Qaeda ties, fought the Lebanese army last year in a months-long battle that left hundreds dead.
On Aug. 13, just hours before newly selected Lebanese President Michel Suleiman paid a landmark visit to Damascus, a roadside bomb struck a bus in the northern Lebanese city of Tripoli, killing at least 12 people, 10 of them soldiers of the Lebanese army, which is widely perceived as sympathetic to Syria. Dozens have died in clashes between Sunnis and Lebanon's Alawite sect, which also has strong ties to Syria.
Lebanese scholar Ahmad Moussalli said he told several Syrian officials over lunch in Damascus three weeks ago to expect an attack on their soil. Saturday's bombing, he said, was unsurprising.
"This constitutes payback against Syria because it is anti-Islamist and is against the spread of such Islamism in the north of Lebanon," said Moussalli, a professor of political science and Islamic studies at American University of Beirut.
Syria suffers strained ties to some Sunni Arab countries over its support for the Shiite political and military organizations Hezbollah in Lebanon and Hamas in the Palestinian territories, as well as its strategic alliance with Shiite-dominated Iran.
Although diplomats all over the world, including U.N. Secretary-General Ban Ki-moon and U.S. State Department officials, condemned the bombing, Saudi Arabia, Damascus' biggest Arab rival, remained silent. The Saudi government staunchly supports Lebanon's Sunni community and Palestinian Authority President Mahmoud Abbas' Fatah movement, which is strongly opposed to Hamas.
Syrian officials and pundits throughout the Middle East have publicly suggested that groups in Lebanon, Saudi Arabia or Israel could have been behind the blast. But authorities investigating the explosion have been mum.
"You can always round up the usual suspects," Moubayed said. "It's too early to blame any particular group or organization."
In a report cited by Israeli media, London's pro-Saudi newspaper Asharq al Awsat said the bombing took place near a building identified as the Palestine branch of Syria's military intelligence. It cited unnamed sources saying that one victim, perhaps the target, was a high-ranking intelligence officer.
But a Syrian opposition group, the U.S.-based Reform Party of Syria, discounted that possibility, saying that no high-ranking officials ever spent time at that intelligence office.
The privately owned Syrian newspaper Al Watan cited witnesses at the site, including a traffic policeman injured in the blast, who said they saw two charred bodies in the black sedan that held the car bomb minutes after the explosion. Imad Habib, the policeman, said he found the car "totally burnt and in it were two burnt persons and another two outside it. They were all dead."
Another witness said the car blew up after crashing into a truck parked along a sidewalk.
The government-run Al Thawra newspaper published an editorial calling for tighter restrictions on foreign visitors. Syria now lets citizens of other Arab countries enter without visas.
"We need to be very careful in whom we let in," the piece said.
"We should ask, 'Why is he here and what does he want?' "