In other violence, a man was shot and killed by an army sniper in the southern city of Daraa, the Observatory said, adding that clashes between troops and rebels raged in the opposition strongholds around Damascus. At least 15 people were killed in the fighting around the capital, the group said.
Daraa province has been the scene of fierce fighting in recent weeks, with rebels making gains in the province and further south.
Last week, they looked poised to take over the area along the Jordanian border, which could be used to try to stage an attack on Damascus, Assad’s seat of power.
Abdul-Rahman said there was little rebel advancement in the province on Sunday, despite rebel forces receiving heavier flows of weapons through Jordan as well as training there by the U.S. and other countries.
In Istanbul, U.S. Secretary of State John Kerry met with Turkish Foreign Minister Ahmet Davutoglu on the first leg of a 10-day overseas trip. They discussed shared U.S. and Turkish efforts to support Syria’s opposition groups, which have struggled to unify and strengthen links with rebels on the battlefield.
‘‘The United States and Turkey will continue cooperating toward the shared goal of a peaceful transition in Syria,’’ Kerry said.
More than 70,000 people have died in the conflict that began in March 2011.
Associated Press writers Jamal Halaby in Amman, Jordan, Albert Aji in Damascus, Syria, and Bradley Klapper in Istanbul contributed to this report.