BEIRUT/UNITED NATIONS - The United Nations hopes to retrieve 21 peacekeepers from Syrian rebels on Saturday during a two-hour truce agreed to by Syrian troops and opposition groups after a release bid was abandoned on Friday, the United Nations and an opposition group said.UN peacekeeping chief Herve Ladsous said the Filipino peacekeepers were being held in the basements of four houses in the village of Jamla, near the Israeli Golan Heights, which was being subjected to intense shelling by Syrian troops.The peacekeepers - part of the UN Disengagement Observer Force (UNDOF), which has been monitoring a ceasefire line between Syria and Israel in the Golan Heights since 1974 - were seized by the Martyrs of Yarmouk rebel brigade on Wednesday.The Syrian Observatory for Human Rights, a Britain-based monitoring group, said the warring parties in Syria were aiming for a ceasefire in the area between 10:00 a.m. and 12:00 p.m. (0800 to 1000 GMT) so the peacekeepers could be released.The United Nations said arrangements were made for the handover of the men on Friday, but "due to the late hour and the darkness, it was considered unsafe to continue the operation.""Efforts will continue tomorrow," a UN peacekeeping department spokeswoman said in a statement.Abu Essam Taseel, a rebel spokesman, said a convoy to collect the men had reached Nafea village, about a kilometer (half a mile) east of Jamla, but was unable to venture further because of intense Syrian army bombardment.Syria's nearly two-year civil war has spilled across the Golan Heights ceasefire line and Syria's borders with Lebanon, Iraq and Jordan, threatening to engulf the region. The conflict began as peaceful protests, but turned violent when President Bashar Assad ordered a crackdown on the demonstrations.The UN peacekeepers were seized in Syria a mile (1.6 km) from Israeli-held lines. The Martyrs of Yarmouk rebels had said they would handover the peacekeepers once government forces retreated from around Jamla and halted bombing there."(Jamla) is subject to intense shelling by the Syrian armed forces," Ladsous told reporters after briefing the UN Security Council on the situation.He also warned that once the peacekeepers were released, "we would strongly expect that there would not be retaliatory action by the Syrian armed forces over the village and its civilian population."Syrian UN ambassador Bashar Ja'afari told reporters that the army was targeting areas outside Jamla where he said the rebels were concentrated, not the village itself."We know for sure what we are doing and we know where the peacekeepers are," he said."The Syrian government forces are doing exactly what they have to do in order to bring back safely the peacekeepers, guarantee the safety and security of the inhabitants of these villages (and) get these armed group terrorists out of the area," Ja'afari said.