Image credit: AP Photo

Russia, the most steadfast ally of Syrian President Bashar Assad's regime, today joined the international condemnation of the brutal massacre of more than 100 people, most of whom were women and children, laying the "main responsibility" for the continued bloodshed in the 15-month uprising on the government.

"Both sides have obviously had a hand in the deaths of innocent people, including several dozen women and children," Russian Foreign Minister Sergey Lavrov said today. "This area is controlled by the rebels, but it is also surrounded by government troops.

"The guilt has to be determined objectively," Lavrov said. "No one is saying that the government is not guilty, and no one is saying that the armed militants are not guilty."

In some of Russia's sharpest criticism yet, Lavrov said the Syrian government "bears the main responsibility for what is going on" by failing to keep its citizens safe.

Conflicting accounts of how the massacre Friday in Houla, a collection of villages in the province of Homs, unfolded make it unclear who is to blame for the killings, . Some anti-government activists said Assad's forces attacked the villages with artillery after protests on Friday. Other activists say the majority of the bloodshed came when pro-regime thugs gunned down men in the street and stabbed women and children in their homes.

The Syrian government told a much different story, saying that the army was just fighting back after rebels attacked their bases.

Despite the differing accounts, the massacre in Houla - the worst single  day of bloodshed since a U.N.-brokered ceasefire was supposed to go into effect on April 12 - led to an outcry from the international community, calling for both sides to lay down their weapons.

"I am personally shocked and horrified by the tragic incident in Houla two days ago, which took so many innocent lives, children, women and men," U.N. envoy Kofi Annan said today when he arrived in Damascus for talks with Assad and Syrian officials.

Annan called on both sides of the conflict to lay down their weapons, saying "this message of peace is not only for the government, but for everyone with a gun."

The U.N. Security Council called an emergency session Sunday, condemning the killings in Houla but avoiding placing explicit blame on either side. It did, however, criticize Syrian forces for attacking residential areas with artillery.

The Council said "those responsible for acts of violence must be held accountable," and enlisted the U.N. observer mission in Syria and Secretary-General Ban Ki-moon to investigate the killings.

Of the estimated 108 people who were killed in the massacre, U.N. observers counted 49 children and 34 women among the dead.

The Associated Press contributed to this report.