UN observers have visited the central village of Tremseh, where more than 150 people were killed this week, according to a spokeswoman for the UN mission and an activist on the ground.

The AFP news agency, quoting an activist in Hama province, going under the name Abu Ghazi, said the observers had met residents of the village and "inspected places that were bombed and where there were traces of blood".

Sausan Ghosheh, UN spokeswoman confirmed that a group of observers had entered Treimsa.

"They entered Treimsa. The convoy is around 11 vehicles in total," she told AFP.