International envoy, Kofi Annan 

AP

International envoy Kofi Annan says he is "shocked and appalled" by reports of a mass killing in the Syrian village of Tremseh.

Syrian activists have posted videos they say show at least 17 of the dozens of people reportedly killed in heavy government shelling of a farming village in central Syria on Thursday, reports The Associated Press.

Annan brokered a peace plan for Syria that has been widely flouted by both sides of the conflict. On Friday, he singled out the government for criticism — saying the Tremseh killings violate "the government's undertaking to cease the use of heavy weapons in population centers."