Two Austrian peacekeepers were shot and killed Friday while patrolling the Golan Heights, officials said.
A U.N. spokesman in Damascus, speaking on customary condition of anonymity, said it was not clear who shot the peacekeepers.
But Fred Eckhard, spokesman at the U.N. headquarters in New York, said the attack appeared to be criminal.
He said spent AK-47 cartridges were found at the site near Hadar, 30 miles southwest of Damascus.
Syrian police and the U.N. force are investigating, Eckhard said.
Some 1,000 peacekeepers from Austria, Canada, Japan and Poland are based on the Golan Heights.