WASHINGTON, Jan 11 (Reuters) - A small team of U.S. military personnel entered southern Somalia to try to determine who was killed in a U.S. airstrike targeting suspected al-Qaeda figures, The Washington Post reported, citing U.S. sources. The report Friday said the search team marks the first known case of U.S. military boots on the ground in Somalia since a disastrous peacekeeping mission ended in 1994 after Somali militiamen downed two Black Hawk helicopters and killed 18 U.S. soldiers in Mogadishu. It was unclear on Thursday whether the U.S. search team remained inside Somalia, The Washington Post reported. U.S. officials have have been cautious about sending American military personnel into Somalian territory, but after Monday's attack it was seen as a necessary risk to positively identify the casualties, the newspaper said. A U.S. air strike on Somalia on Monday killed up to 10 al Qaeda-affiliated "terrorists," but three of the most wanted suspects survived, a senior U.S. official based in East Africa told reporters on Thursday. The official, speaking on condition of anonymity, dismissed reports that U.S. special forces were in Somalia. A U.S. warplane attacked a village in southern Somalia on Monday in an attempt to destroy an al Qaeda cell accused of bombing two U.S. embassies and an Israeli-owned hotel in East Africa.