The Free Syrian Army (FSA) took responsibility for the blast, which reportedly targeted a meeting of military officers at the compound in the heavily guarded Arkan neighborhood of Damascus and underscored that top officials remain vulnerable to such rebel attacks.
No U.N. monitors staying at the nearby Dama Rose hotel were injured in the explosion that came as their four-month monitoring mission was coming to an end.
“We promise this criminal regime more targeted and large operations to come inside the capital that will break his back until it reaches the presidential palace,” read a joint statement by the two FSA militias that said they carried out the attack.
The FSA said it received inside help in the bombing and that the attack was carried out in response to massacres of Syrian civilians by government forces loyal to President Bashar Assad. It was also avenging the recent killing of a media activist who was the spokesman for one of the militias, the statement said.
Damascus activist Moaz Shami said it was unlikely the rebels acted without help from someone inside the compound. The neighborhood is one of the most protected areas in the capital, he said.
“It is not possible for the Free Syrian Army to penetrate this building,” he said. “It is impossible for them to be able to enter like that and plant a bomb.”
A bombing last month that killed four of Assad's top security officials was also thought to have been done with inside help.
State media reported that the explosive device used Wednesday was attached by an “armed terrorist group” to a diesel tanker and resulted in minor damage to surrounding buildings.
Video from the blast aftermath showed black plumes of smoke and fire rising from a building just a few feet from a row of parked U.N. vehicles.
“The terrorist explosion is another attempt by those who seek to distort the civilized image of Syria and its people," said Deputy Foreign Minister Fayssal Mikdad, speaking to reporters at the Dama Rose hotel.
The explosion was part of a larger campaign against Syria coming from inside and outside the country, Mikdad was quoted as saying by the Syrian Arab News Agency.
Since the beginning of the uprising last year, the Syrian regime has continued to present the call for Assad’s ouster as a foreign plot.
"Syria will not be affected by such terrorist explosions and will continue its cooperation with the United Nations and will exert all efforts to protect its mission and enable observers to play their role appropriately,” he said.
Elsewhere in the capital, fierce fighting broke out in Mezze, a neighborhood largely supportive of the uprising, after rebels said they had targeted the Iranian Embassy and the prime minister's offices as well as nearby government checkpoints.
Clashes in Damascus have ebbed in recent weeks after a rebel offensive in mid-July was crushed by government forces. But fighting has begun to pick up slightly as the rebels nurse ambitions to eventually take over the city.
-- Times staff
Photo: An image released by the Syrian opposition's Shaam News Network on Wednesday purports to show smoke billowing from the scene of a bomb explosion in central Damascus near a meeting of Syrian military officials and a hotel used by the U.N. observer mission. Credit: Shaam News Network / Agence France-Presse