BEIRUT — U.N. officials in Syria are starting to close down their military observer mission after failed international attempts to broker a cease-fire.

Military monitors in Damascus started to pack up on Friday. The U.N. plans to keep a small new liaison office to support any future peace efforts.

The Security Council decision to end the mission this coming Sunday underscores the frustration of U.N. officials who tried to ease Syria's bloodshed. The U.N.'s assistant secretary-general for peacekeeping,
Edmond Mulet, says both sides have "chosen the path of war."

The developments come amid stepped up offensives by Bashar Assad's regime, including air strikes on a rebel stronghold in northern Syria and shelling in the country's largest city, Aleppo. Activist say 20,000 people have died in the more than 17-month-old civil war.