Syrian activists said Saturday more than 90 people, including many children, had been killed in the last 24 hours in a coordinated assault by government forces and militiamen on a village near the central city of Homs.

Damascus did not deny the massacre but blamed unidentified “terrorists” for one of the deadliest incidents since an uprising against President Bashar al-Assad began 15 months ago.

A team of United Nations observers, headed by General Robert Mood, arrived in the village Saturday to investigate the killings. The general condemned the “brutal tragedy” and said the observers counted more than 32 children under the age of 10 and over 60 adults killed.

Amateur video showed families burying the dead from Friday's massacre. Witnesses said the killing began when government forces shelled the village after Friday prayers. They said some of the victims were killed in the shelling, while others were shot dead by pro-government militiamen known as “shabiha.”

United Nations Secretary-General Ban Ki-moon and the U.N.-Arab League envoy for Syria, Kofi Annan, condemned the violence. The two described the attacks as an “appalling and brutal crime involving indiscriminate and disproportionate use of force.”

Thousands of mourners turned out Saturday in Syria's largest city, Aleppo, to protest the killings, which struck another blow to a fragile six-weeks-old cease-fire brokered by Annan. Close to 300 U.N. monitors are now on the ground in Syria to observe the situation.

In the Qaddam district of Damascus, government forces opened fire on mourners, causing a large crowd to scatter in all directions. It is not clear if there were any victims.

French Foreign Minister Laurent Fabius on Saturday called for a meeting in Paris of the Friends of Syria, a group attempting to remove Syrian President Bashar al-Assad from power, while the opposition Syrian National Council urged the U.N. Security Council to convene an emergency session.

The violence in Syria has continued despite a peace plan brokered by Annan. A spokesman for the former U.N. secretary-general said Mr. Annan would travel to Syria soon for his first visit since presenting the peace plan in March.

Syria's unrest is having an impact in northern Lebanon, where ethnic clashes between opponents and supporters of President Assad have left at least 11 people dead and more than 100 wounded in recent days.

The U.N. says more than 10,000 people have been killed in Syria since the government began its crackdown on dissent in March 2011.