Two international peacekeepers are missing in Sudan's Darfur region after armed men ambushed their patrol and held the force overnight, officials said on Saturday, according to Reuters. Unidentified gunmen surprised the joint U.N./African Union UNAMID patrol on Friday afternoon as it was on its way to investigate reports of heavy fighting in Darfur's central Jabel Mara region, the force said. UNAMID said the attackers took the patrol to a nearby settlement and detained the men overnight before releasing them on Saturday morning. "It was then they found two peacekeepers were unaccounted for," UNAMID communications chief Kemal Saiki told Reuters. "We don't know their whereabouts or how they came to be missing ... Did they flee during the ambush trying to make their way back to base? We don't know." Hundreds of civilians are feared to have died in a surge of fighting between Sudan's army and rebels in the mountainous Jabel Marra area, a U.N. source and rebels told Reuters last week. Sudan's army denies involvement in fighting in the area. The reported clashes with a faction of Darfur's rebel Sudan Liberation Army (SLA) came as Sudan's government agreed a ceasefire with another insurgent force in Qatar's capital Doha. The 60-strong UNAMID patrol, including soldiers and military observers, set off from the capital of South Darfur Nyala towards the Jabel Marra town of Deribat on Friday and were ambushed around midday, said Saiki. "We were conducting an important security and humanitarian patrol in order to determine what happened to the civilian population in Jabel Marra and what sort of assistance they needed," Saiki added. "Apparently this did not please some people ... They used violence and intimidation to prevent our mission." AWAITING REPORT Saiki said UNAMID was waiting for a detailed report from the patrol which moved to a nearby town after being released. "There have been some contradictory reports ... We are putting all our efforts into trying to determine (the two peacekeepers') whereabouts." Saiki said there was no information on the identity of the attackers. "The only thing we know for sure is that it happened in an area that the SLA was claiming under its control. But that does not signify anything." A total of 22 UNAMID peacekeepers have died in incidents since the force arrived in Darfur at the start of 2008. Law and order has collapsed in Darfur since the conflict flared in 2003 when mostly non-Arab rebels took up arms against the government of Sudan, accusing it of neglecting the region.