Syria's fragile, United Nations-backed cease fire, if it can even be called a cease fire, could be in grave jeopardy after a deadly suicide bombing struck a major Syrian intelligence facility.

The strike, which has killed at least 50 people and wounded hundreds more, was timed right for rush hour when the most people would be on the street and near the doors where the bomb blast was triggered.

According to The New York Times, the explosion in front of the Syrian intelligence building left "a grisly scene on the crowded highway in front of it, with incinerated corpses and many burning vehicles emitting plumes of black smoke visible across the capital. Pictures of the gruesome, bloody wreckage with severed body parts scattered about were shown repeatedly on state television."

The blast was believed to be caused, according to various reports, by more than 2,200 pounds of explosives packed into two vehicles.

According to the Times, the attack is the deadliest by rebels since their efforts to force President Bashar al Assad from power more than a year ago.

“This is yet another example of the suffering brought upon the people of Syria from acts of violence,” Norwegiean Maj. Gen. Robert Mood said, according to the Times. “We, the world community, are here with the Syrian people, and I call on everyone within and outside Syria to help stop this violence.”

Wood is heading up the U.N. peacekeeping mission.

According to the BBC, U.N. special envoy to Syria Kofi Annan harshly criticized the suicide bombing as abhorrent. Annan created a peace plan that, ostensibly, was agreed to by all sides, but so far has proven elusive.

Overnight, for example, the key city of Homs was shelled by Syrian forces, the BBC said.

The targeted building is home to "the Palestine Branch, one of the most feared among the more than 20 secret police organisations in the country, correspondents say. The unit was originally set up in the 1950s to interrogate suspected Israeli spies," the BBC wrote.

It's evolved into the country's counter-terrorism force, widely known for using torture in its interrogations.

Proving just how on-edge Syria is, one Damascus resident told the BBC that the blasts were the largest he'd ever heard.

"The whole of Damascus heard them. At first, I thought they were air strikes," he said to the British broadcaster.