The last-minute decision by China to bar the visit was highly unusual.

China turned the ships away when they neared the port for the planned four-day stop. It later reversed its decision, but by that time the aircraft carrier, along with four warships and a nuclear submarine, were already leaving the area under heavy weather.

Beijing has given no reason why it refused the ships entry.

"The crew members were disappointed, but that did not deter them from celebrating Thanksgiving on the ships with meals and movies," said Lt. Cmdr. Steven Curry, a spokesman for the 7th Fleet, which has its home port in Yokosuka, just south of Tokyo.

The Kitty Hawk and its strike group were on their way back to Yokosuka on Friday, he said.

Hundreds of sailors' families had flown to Hong Kong to spend the holiday with their loved ones, while dozens of Americans living in Hong Kong had prepared turkey dinners for those without relatives.

Curry said the development was a surprise.

"It had been planned for several months," he said. "We go there many times a year."

China has in the past barred U.S. Navy ships from Hong Kong over disputes in relations.

In recent weeks, ties have been strained over Congress's awarding a medal to the Dalai Lama, the Tibetan spiritual leader whom China's Communist government considers an enemy. The Dalai Lama is currently in Japan.

China and the U.S. have also increasingly been at odds over Beijing's swelling military budget and rapidly modernizing naval and air forces. Last year, a Chinese submarine surfaced just 9 kilometers (5 miles) away from the Kitty Hawk and its escorts during exercises off Okinawa.

Hong Kong has long been a favored port of call for the U.S. military but Beijing's approval has been required since July 1, 1997, when Britain handed the former colony back to China.

In Hong Kong, port officials said they had not been notified of the previously scheduled visit. Asked repeatedly about Beijing decision, China's foreign ministry spokesman Liu declined to comment.

In reversing its position, Beijing indicated that it was only grudgingly going to allow the ships in.

"We have decided to allow the Kitty Hawk strike group to stay in Hong Kong during Thanksgiving, and it is a decision out of humanitarian consideration only," Liu told reporters at a regular media briefing in Beijing later Thursday. "China has informed the U.S. of this."

U.S. Navy officials said that by the time Beijing had changed its mind, the ships were already 400 kilometers (250 miles) away from the port.

"After the USS Kitty Hawk carrier strike group had been refused entry into the port of Hong Kong, building seas and deteriorating weather conditions necessitated the strike group's departure from the area," the 7th Fleet said in a statement.