BEIRUT, Lebanon - Two weeks into a cease-fire agreement, there still was no peace in Syria: Security agents in Damascus collected the remains of 10 people killed in a suicide bombing. Activists reported troops firing on protesters. Video showed a crowd carrying a slain boy to U.N. observers as proof of regime violence.

The head of the United Nations said Syrian President Bashar al-Assad's continued crackdown on protests has reached an "intolerable stage," and that the U.N. will try to speed up the deployment of up to 300 monitors to Syria. Only 15 are there now.

"The government of Syria must live up to its promises to the world," U.N. Secretary-General Ban Ki-moon said Friday.

Tens of thousands of people poured into the streets across Syria for weekly anti-regime marches after Muslim noon prayers Friday. Amateur video from the central city of Homs, where the presence of U.N. observers helped halt weeks of artillery attacks, showed rows of men lining up in a main street, holding each other by the shoulders as they sang and danced.

In another protest, demonstrators held up 45 squares of cardboard with writing and drawings that - when viewed together from above - showed a picture of Assad and the words "oppression, corruption, despotism, demolition." When they simultaneously flipped over the squares, it created a new message that read: "Toward a modern society that is more developed and sensible."

Troops have routinely opened fire on protests since the uprising against Assad began 13 months ago, but there appeared to be fewer violent incidents Friday than in previous weeks. Still, the Britain-based Syrian Observatory for Human Rights said five protesters were killed by fire from the security forces, including a 10-year-old boy.

A plan brokered by special envoy Kofi Annan proposed an April 12 cease-fire, to be followed by talks between the regime and the opposition. Since that date, the United Nations has said the regime has broken many of its truce promises, such as withdrawing forces from towns and cities. Rebel fighters have also kept up shooting and bombing attacks on Syrian security forces.

With the United States and France in the lead, Western powers have threatened tougher U.N. Security Council measures if Assad keeps breaking his promises, although Syria's allies Russia and China could use their veto powers in the council to shield him.

British Foreign Office Minister Alistair Burt said his government will seek "robust action" in the council if Syria doesn't comply with Annan's plan.

The suicide bomber in Damascus detonated an explosives belt Friday near members of the security forces, killing at least nine people and wounding 26, the state-run news agency SANA reported. The remains of two other people also were found, one believed to be the bomber, according to Health Minister Nader al-Halqi. The minister said seven police were among the dead.

The blast went off near a mosque in the downtown Midan neighborhood, an area of opposition sympathizers. The government said it would use an iron fist against those "who might intimidate residents and spread anarchy in the country," SANA reported.