TOKYO, Japan (CNN) -- A high-level American delegation may be headed to Okinawa soon to smooth strained relations with Japan after allegations a U.S. Marine raped a Japanese teenager.

Japanese Prime Minister Yasuo Fukuda on Tuesday deplored the incident as "unforgivable."

Okinawa authorities are bracing for protests if Staff Sgt. Tyrone Luther Hadnott, 38, is charged in the alleged Sunday night attack on a 14-year-old girl.

In Washington, U.S. State Department spokesman Sean McCormack said, "It's a horrendous crime, and we take these allegations very seriously. We are working very closely with Japanese officials on the matter."

McCormack suggested an American delegation soon might meet with the family of the alleged victim or local officials, he said.

"I would expect there would be some senior-level U.S. visitors, not from the U.S. but from inside Japan, who might make a trip down there to Okinawa," he said.

He wouldn't give any details other than to say such a visit might include the U.S. ambassador to Japan, Thomas Schieffer, and a top U.S. military officer.

The episode echoes a similar incident more than a decade ago that strained relations between the United States and Japan. Watch as the new case strikes a raw nerve in Okinawa »

In 1995, anti-U.S. sentiments boiled over when three American servicemen gang-raped a 12-year-old Okinawan schoolgirl. Two years ago, a U.S. civilian military employee was jailed for nine years for raping two women.

"There have been incidents like this in the past, and it is a problem that it has occurred again," Fukuda told a parliamentary panel Tuesday. "We take this very seriously."

Also Tuesday, the deputy police chief of Okinawa City released more details of the case, saying Hadnott offered to take the girl home on his motorcycle.

The schoolgirl, he said, was walking with her friends and accepted Hadnott's offer.

According to police, Hadnott took the girl to a house and later to his car. They drove to a park where he allegedly attacked her, police said. The girl used her cell phone to call friends, who notified police.

Hadnott reportedly told authorities he only tried to push the girl down and kiss her. The girl disputed his claims, and police said they intend to file rape charges. Under Japanese law, a person can be held up to 10 days without charges.

The assault was reported Sunday night in the Chatan entertainment district on Okinawa, a major hub for U.S. forces in the Pacific.

Hadnott is based at Camp Courtney there. More than 40,000 U.S. troops are stationed in Japan, most of them in Okinawa. They were placed there under a security alliance after Japan was defeated in World War II and forced to renounce its right to a military.

The servicemen's presence has at times bred resentment among local residents who have long complained about crime, noise and accidents. E-mail to a friend

CNN's Kyung Lah and Charley Keyes contributed to this report.

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