The United Nations called off an effort to secure the release of 21 Filipino peacekeepers held by a Syrian rebel group until Saturday because of darkness in the Golan Heights, a UN spokeswoman said.
Syrian activists had said earlier that a UN convoy left the village of Jamla because it came under attack from Syrian government forces.
"Arrangements were made with all parties for the release of the 21 peacekeepers" from the UN Disengagement Observer Force (UNDOF), said UN peacekeeping spokeswoman Josephine Guerrero.
"UNDOF dispatched a team to the location but due to the late hour and the darkness it was considered unsafe to continue the operation. Efforts will continue tomorrow," Guerrero added.
Syrian activists said the Syrian army had attacked Jamla.
"When the UN vehicles entered into Jamla, the Syrian army shelled a nearby village. The UN cars then withdraw from Jamla," said Syrian Observatory for Human Rights director Rami Abdel Rahman.
The peacekeepers were detained on Wednesday by a rebel group, the Yarmuk Martyrs brigade, which is fighting President Bashar al-Assad's forces.