Ambassador Howard Baker's comments, to a small group of journalists at the U.S. Embassy, came as Japanese officials — including Prime Minister Junichiro Koizumi — said the 64-year-old American should be taken to Japan for medical treatment.
Japanese media reported that Jenkins could come to Japan as soon as Sunday. But Koizumi and other government officials said that no date had yet been set for Jenkins' arrival.
"We are still trying to make final arrangements" for Jenkins' visit, said Chief Cabinet Secretary Hiroyuki Hosoda. Asked how soon Tokyo would reach a decision, Hosoda said: "It will be soon."
Baker said the U.S. government was "sympathetic" to Jenkins' unspecified health problems, and that Washington was not insisting he be treated at a U.S. military hospital if he came to Japan.
"If and when he comes to Japan we will ask for custody — exactly when remains to be seen," Baker said.
"It's certainly possible he could come to Japan, that the United States would insist on its rights, but that actual custody would not be sought or consummated under some circumstances," the ambassador added.
Jenkins, a North Carolina native, is accused of abandoning his U.S. Army unit on the Demilitarized Zone between North and South Korea in 1965 and defecting to the North. He has lived in the communist state since then, and has appeared in Northern propaganda films.
Since last week, Jenkins has been in Jakarta, Indonesia, meeting with his Japanese wife, Hitomi Soga. Soga was kidnapped by Northern agents in 1978 and the two were married in North Korea, but Soga was allowed to return to Japan in 2002. Jenkins and his two daughters remained in North Korea for fear of U.S. prosecution.
Jenkins has apparently never been processed out of the military and presumably would be subject to U.S. military arrest and court-martial were he to return to Japan, where some 50,000 U.S. troops are based.
The Japanese government, eager to have Soga's family reunited in Japan, has urged the United States for leniency in Jenkins' case so he could come to Japan without being arrested.
The case has been complicated by Jenkins' health troubles.
He was being examined by Japanese doctors in Indonesia, which doesn't have an extradition treaty with the United States. The doctors have recommended he be sent to Japan for further care.
In Jakarta on Thursday, Soga issued a statement urging that Jenkins be allowed to be treated in Japan.
"We are very worried about the health of my husband," the statement said. "I wish for him to have treatment in a Japanese hospital and my hope is that we can return to Japan and live as a family."
National broadcaster NHK reported on Thursday that Jenkins suffers from peritonitis, an inflammation of the walls of the abdomen that can become serious if not properly treated.
"I think it's better he receive treatment in Japan," Koizumi said.
Hosoda said earlier in the day that Washington and Tokyo had still not reached an agreement on how to treat Jenkins' legal case, and that attention to his health problems could come first.
"There is a possibility that Mr. Jenkins may have to receive treatment before we reach a final agreement," he said.
He added that Jenkins, who underwent surgery on his abdomen in North Korea, may need another operation, according to the Japanese doctors.
Baker said the United States had not swerved from its determination to pursue a case against Jenkins.
"As and when we can gain custody of him, he will be charged. With what and when and on what basis, I can't tell you," Baker said. "But it will be treated as the very serious incident that it is."
However, the ambassador said Washington appreciated the severity of Jenkins' medical troubles.
"The United States government is sympathetic to his health condition, his family arrangements and circumstances — we understand all that," he said.
"This man is in terrible shape," Baker added. "His health circumstances are really barely short of extreme. I have no doubt that he's in need of skillful medical attention."