A jihadist insurgent group that Western intelligence officials have linked to Al Qaeda claimed responsibility on Tuesday for a multiple bombing by suicide attackers who struck an intelligence compound on the outskirts of Damascus overnight. It was the second major assault that the group has claimed to have carried out against a government facility in a Syrian urban center in about a week.
The group, Al Nusra Front for the People of the Levant, posted a statement on the Internet with details of what it called a three-stage attack on a compound run by a branch of the air force intelligence service in Harasta, on the edge of Damascus. It released a video showing nighttime blasts that it said were set off by vehicles packed with explosives.
The number of casualties from the attack was not known, and the Syrian state news media did not immediately report on it. On Oct. 3, the same group posted a statement on a Web site affiliated with Al Qaeda that claimed responsibility for explosions in the embattled northern city of Aleppo that killed dozens of people in areas held by the government, including an officers’ club.
The attacks have highlighted a worrisome theme in the Syrian conflict, in which Sunni extremist groups like the Nusra Front, some of which are suspected of having links to Al Qaeda, are claiming responsibility for deadly attacks on government targets, including suicide bombings, with increasing frequency. While the main opposition fighting force, the Free Syrian Army, has denied any ties to such groups, their presence has strengthened President Bashar al-Assad’s argument that the nearly 19-month-old uprising is being orchestrated by terrorists.
The Nusra Front gave details about the operation in the Damascus area, like the name of the man who drove the car laden with what it said was nine tons of explosives in the first stage of the operation. Twenty-five minutes later, another man drove an ambulance laden with explosives to the scene, to kill those remaining or coming to assist, the group said. Shelling followed.
Fighting was also reported on Tuesday in other areas, including Aleppo, Syria’s largest city, and Deir al-Zour, in eastern Syria. The Local Coordination Committees, an opposition group, said in its daily tally of violence that at least 115 people had been killed and that in Maaret al-Nouman, in Idlib Province, the Free Syrian Army had captured more than 40 government troops and seized weapons. Casualty claims by antagonists in the Syria conflict are often difficult to confirm because of restrictions on independent news reporting there.
The latest violence came as the Syrian military continued to divert some forces and firepower to face escalating tensions on its border with Turkey, a NATO member. On Monday, Syrian Army gunners exchanged artillery blasts with their Turkish counterparts across the frontier for the sixth consecutive day.
The exchange of fire has raised concerns that the conflict will ignite a broader crisis in the region. On Tuesday, the NATO secretary general, Anders Fogh Rasmussen, emphasized that NATO, which considers an attack on one member to be an attack on all, had “all necessary plans in place to protect and defend Turkey if necessary.”
But Mr. Rasmussen also made it clear that he had no desire to embroil NATO in the conflict.
While most Syrian insurgents are members of the country’s Sunni majority, many of them defectors from the military, much of the Alawite minority, which Mr. Assad belongs to, remains intensely loyal to him. Nonetheless, recent signs of fracturing have surfaced in his Alawite base, including unconfirmed reports of deadly clashes last weekend in his ancestral home, Qardaha, a village in Latakia Province, which borders Turkey.
In another possible signal of Alawite ambivalence about Mr. Assad’s political leadership, opposition figures in Syria and in neighboring Jordan said that as many as seven high-ranking Alawite military and intelligence officers had defected in recent days, with some saying they had entered Jordan.