Friday's assault on the town of Houla was one of the most violent events in Syria's 15-month uprising.
Activists said a militia working for the government is responsible. But Foreign Ministry spokesman Jihad Makdissi denied government troops were behind the attack, instead blaming armed terrorist groups.
The attacks sparked outrage from American and other international leaders, and renewed concerns about the relevance of a 6-week-old international peace plan that has not stopped almost daily violence. The U.N. put the death toll weeks ago at more than 9,000. Hundreds have been killed since. U.N. envoy Kofi Annan will travel to Syria on Monday.
The Associated Press contributed to this report.