A U.S. soldier has admitted he may have run over a Japanese man found dead two weeks ago on the southern island of Okinawa, his lawyer said on Friday, in a case that may further strain ties between the two countries, according to Reuters. Under an agreement that irritates many in Okinawa, U.S. forces based there are not obliged to hand over personnel suspected of a crime outside the base unless they are charged, though they have sometimes done so in serious criminal cases. The case comes as Japan and the United States are locked in a feud over the relocation of a U.S. Marine air base on Okinawa, which is home to about half of the 47,000 U.S. troops stationed in Japan. U.S. bases cover nearly 20 percent of the tropical resort island. Prime Minister Yukio Hatoyama, who has vowed to build a more equal relationship with Japan"s biggest security ally, called this month for the soldier to be transferred to Japanese police custody if he was involved in the fatal incident. "The longer it continues, the more frustrated people in Okinawa will become," Kyodo news agency quoted Hatoyama as saying on Thursday. "I hope they (the U.S. military) will cooperate toward an early resolution." Okinawa police found bloodstains on a car driven by the U.S. soldier matched the blood of the victim, the deputy chief at Kadena police station in Okinawa told Reuters. The soldier, who had previously denied involvement in the incident, then said he may have hit the man, his lawyer, Toshimitsu Takaesu, said by phone. The soldier said he thought he had hit a tree on the road and wanted to apologise and pay reparation to the victim"s family, Takaesu said. The U.S. soldier has been questioned by local police several times on a voluntary basis but has refused to comply with requests to do so since Saturday and is being held by the U.S. military, police said. The alliance between the two countries has been jolted before by military accidents and crimes. The 1995 rape of a 12-year-old girl by U.S. soldiers based in Okinawa prompted huge anti-base protests.