DAMASCUS, Syria May, 10 (AP/UNB) — Two strong explosions ripped through the Syrian capital Thursday, heavily damaging a military intelligence building and leaving blood and human remains in the streets.

The death toll was not immediately clear.

An Associated Press reporter at the scene said ambulances were trying to reach the victims in the capital's Qazaz neighborhood.

The blasts happened at about 7:50 a.m., when employees are usually arriving at work.

Central Damascus is tightly under the control of forces loyal to President Bashar Assad but has been struck by several bomb attacks, often targeting security installations or convoys.

The latest major explosion in the capital occurred on April 27 when a suicide bomber detonated an explosives belt near members of the security forces, killing at least nine people and wounding 26.

Syria's conflict started in March 2011 with mass protests calling for political reform. The government swiftly cracked down, dispatching tanks, troops, snipers and pro-government thugs to quash dissent, and many members of the opposition took up arms to defend themselves and attack government troops. Many soldiers also switched sides.

The U.N said weeks ago that more than 9,000 people had been killed. Hundreds more have died since.

International diplomacy has failed to stop the bloodshed, and the U.N. has ruled out military intervention of the type that helped bring down Libya's Moammar Gadhafi, in part out of fear that it could exacerbate the violence.

On Wednesday, a roadside bomb hit a Syrian military truck in a southern province just seconds after the head of the U.N. observer team was driving by in a convoy, demonstrating the fragility of the international plan to end the country's bloodshed.

In Washington, meanwhile, President Barack Obama took steps to extend sanctions against Assad's government, saying Syria poses an "unusual and extraordinary threat" to U.S. national security and diplomatic goals.