DAMASCUS, Syria — Twin suicide car bomb blasts ripped through an upscale Damascus district today, targeting heavily guarded intelligence buildings and killing at least 40 people, Syrian authorities said.

The blasts came a day after an advance team of Arab League observers arrived in the country to monitor Syria’s promise to end its crackdown on protesters demanding the ouster of President Bashar Assad. Government officials took the observers to the scene of the explosions and said it backed their longtime claims that the turmoil is not a popular uprising but the work of terrorists.

The blasts were the first such suicide bombing in Syria since the uprising began in March.

“We said it from the beginning, this is terrorism. They are killing the army and civilians,” Deputy Foreign Minister Faysal Mekdad told reporters outside the headquarters of the General Intelligence Agency, where bodies still littered the ground. State TV said initial investigations indicated possible involvement by the al-Qaida terror network.

Alongside him, the head of the observer advance team Sameer Seif el-Yazal said, “We are here to see the facts on the ground... What we are seeing today is regretful, the important thing is for things to calm down.”

An opposition leader raised doubts over the authorities’ version of the events, suggesting the regime was trying to make its case to the observers.

Omar Idilbi, a member of the Syrian National Council, an umbrella group of regime opponents, called the explosions “very mysterious because they happened in heavily guarded areas that are difficult to be penetrated by a car.”

“The presence of the Arab League advance team of observers pushed the regime to give this story in order to scare the committee from moving around Syria,” he said, though he stopped short of accusing the regime in the blasts. “The second message is an attempt to make the Arab League and international public opinion believe that Syria is being subjected to acts of terrorism by members of al-Qaida.”

The blasts went off outside the main headquarters of the General Intelligence Agency and a branch of the military intelligence, two of the most powerful of Syria’s multiple intelligence bodies.