BEIRUT — U.N. observers in Syria suspended their activities and patrols Saturday because of escalating violence in the country, the head of the mission said, the strongest sign yet that an international peace plan for Syria is disintegrating.

Maj. Gen. Robert Mood said rising bloodshed over the past 10 days was posing significant risks to the lives of the some 300 observers in the country, and was impeding their ability to carry out their mandate.

The observers were sent to the country after international envoy Kofi Annan brokered a peace plan that included a cease-fire that was supposed to take effect on April 12. But both sides have continued to stage daily attacks and the observers themselves have been caught up in the violence on several occasions.

“U.N. observers will not be conducting patrols and will stay in their locations until further notice,” he said in a statement Saturday. He said the observers will not leave the country, and the suspension will be reviewed on a daily basis.

“Operations will resume when we see the situation fit for us to carry out our mandated activities,” he said.