Japanese media say a U.S. Army sergeant who is accused of deserting his unit in South Korea four-decades ago will be brought to Japan as early as Sunday for medical treatment. But that action could strain ties between the United States and Japan.

Japanese media reports say Charles Robert Jenkins will fly to Japan Sunday and go directly to a hospital. The reports quote Japanese officials as saying Sergeant Jenkins needs treatment for an abdominal inflammation and other medical conditions.

Prime Minister Junchiro Koizumi said he cannot comment about negotiations with the United States concerning Sergeant Jenkins.

Mr. Koizumi, hinting that the issue is far from resolved, says the United States has its own position on the matter.

Sergeant Jenkins, who disappeared from his U.S. Army post in South Korea in 1965, was reunited with his Japanese wife and their two daughters last week in Jakarta.

He met Hitomi Soga in Pyongyang in 1978 after North Korean agents kidnapped her in Japan. Ms. Soga came back to Japan with four other abductees in 2002, but had to leave her husband and daughters behind.

Mr. Jenkins in May said he was afraid to come to Japan because he did not want to be turned over to the U.S. military for court martial.

State Department spokesman Richard Boucher confirmed this week that the United States still wants custody of the alleged deserter at the first opportunity.

"I think they understand our position that Sergeant Jenkins does face potentially serious charges if he is in a place where he is subject to U.S. jurisdiction," said Mr. Boucher.

But U.S. Ambassador to Japan Howard Baker is quoted as saying that Washington might not ask for immediate custody of Mr. Jenkins because it is "sympathetic" to his health problems. Chief Cabinet Secretary Hiroyuki Hosoda says Mr. Jenkins might have to be brought to Japan before any agreement is reached about handing him over to the United States.

Mr. Hosoda says Japan considers bringing Mr. Jenkins to Japan an "emergency lifesaving measure." A Japanese official in Jakarta earlier had said Mr. Jenkins' ailments were not life threatening.