Ban Ki-moon spoke by telephone Saturday with Yang Jiech, China's foreign minister, ahead of the U.N.'s chief's upcoming trip to China and southeastern Europe.

Ban Ki-moon said the U.N. is attempting to verify the facts about reported unacceptable fighting in the Syrian village of Tremseh that involved the use of heavy weapons, a violation of Syria's obligations under Security Council resolutions.

U.N. observers have visited Tremseh, where activists say more than 150 people were killed Thursday. The observers said they found signs that the assault targeted the homes of specific opponents of the regime.

On Friday, U.N. envoy Kofi Annan blamed government forces and armed militiamen for what he called “atrocities” in Tremseh. Syrian state media blamed terrorists for the massacres.

Meanwhile, the opposition Syrian Observatory for Human Rights tells VOA at least 31 people were killed in anti-government-related violence across Syria on Saturday. Activists also say Syrian forces pounded the southern town of Khirbet Ghazaleh.

U.N. Secretary-General Ban Ki-moon departs Monday for China where he will meet with the country's leaders and participate in a forum on China-Africa cooperation.

After China, the U.N. head travels to southeastern Europe, making stops in Slovenia, Croatia, Montenegro, Serbia, Kosovo, and Bosnia-Herzegovina.