A Free Syrian Army officer said his resistance group was responsible for an attack on government headquarters in Damascus on Wednesday.

Lieutenant Abu al-Nour said the headquarters had been completely destroyed while some 150 people were inside, and that none so far had exited the building.

He said the bombing targeted morning meetings of high-ranking lieutenants, which take place at around 8:05 every day during Ramadan, and claimed the headquarters stored weapons used by the Assad regime.

Eight improvised explosive devices were used to destroy the building, he added.

Maher Nuwaimi, head of the FSA coordination command in Syria, told AFP that “the FSA operation targeted a military command office with explosives designed to go off at a meeting of army officers and members of the shabiha (pro-government militia) which decides on daily operations in Damascus.”

Clashes ensued after the bombing hit the parking area of Syrian government general staff headquarter in Damascus, reported Syrian TV.

Later in the afternoon, the opposition group, Local Coordination Committees, reported clashes between FSA and the Syrian regime’s forces behind the Iranian embassy in Damascus.

A witness said the explosion had gone off at around 8.30 a.m. (0530 GMT) and damaged a building opposite the Dama Rose Hotel, where the U.N. monitors were staying, but appeared not to have damaged the hotel itself.

An opposition activist in the capital saw smoke rising from the scene and ambulances arriving to treat the wounded.