There are conflicting reports from Syria about mass killings on 12 July in Tremseh, a village in Hama province.
UN observers have now reached the village but were able to say little other than heavy weapons had been used - a violation of Syria's commitment to a UN-backed peace plan.
The observers saw pools of blood and bullet cases but have not determined the number of dead, who they were, or exactly who carried out the attack.
They did say the attack appeared to target specific houses or buildings used by army defectors or opposition activists.
This runs counter to some of the villagers' accounts, which said that army tanks had randomly bombarded the village for several hours before pro-government militiamen swept in, shooting and stabbing victims, including civilians, at close range. Some reports say up to 200 people were killed.
But the government now says that only 37 people, including two civilians, died in the attack.
It also strongly rejected UN allegations that it used helicopters, aircraft or heavy weapons, saying only troops carriers and small arms, including rocket-propelled grenades, were deployed.
The government said five buildings housing what it termed "armed terrorists" had been targeted and that the area was too small to use tanks.