The top U.S. military commander in the Pacific said he's "perplexed and concerned" by China's last-minute decision to deny a U.S. aircraft carrier entry to Hong Kong for a previously scheduled port visit.

The USS Kitty Hawk and its escort ships were due to dock there for a four-day visit Wednesday until they were refused access. Hundreds of family members had flown to Hong Kong to spend Thanksgiving with their sailors.

"It's hard to put any kind of positive spin on this," Adm. Timothy Keating told The Associated Press in a telephone interview Thursday while flying back to the U.S. after visiting troops in Iraq. "I'm perplexed and concerned."

China later reversed its decision and said the ships could enter on humanitarian grounds, but the notice came while the vessels were already on their way back to their home ports. The vessels chose not to turn around.

Thousands of sailors aboard the Kitty Hawk and its carrier battle group marked the Thanksgiving holiday at sea.

"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.

It was the second time in a week that China refused to let U.S. Navy ships into the port.

Two U.S. minesweepers seeking to refuel and shelter from bad weather in the South China Sea had asked for permission to enter Hong Kong three or four days before the Kitty Hawk. Those ships were denied, Keating said.

The developments come as the U.S. military has been trying to bolster ties with the Chinese military to prevent misunderstandings and the potential for miscalculation.

Defense Secretary Robert Gates visited Beijing earlier this month and high-level commanders have traveled back and forth between the two Pacific powers.

Chinese warships visited U.S. naval bases in Pearl Harbor and San Diego last year, and the two navies have since held basic search-and-rescue exercises together.

Asked if the refusal to let the Kitty Hawk into Hong Kong would hurt the U.S.-China military relationship, Keating said: "We'll keep working it of course, but it is difficult for me to characterize this in a positive light."

The admiral said he would to talk to officials at the State Department and the Pentagon to determine how to respond.

Keating, who heads the U.S. Pacific Command from its Hawaii headquarters, said he was unaware of any reason for China's decision. "It's my understanding the Chinese just said 'no,"' he said.

China has in the past barred U.S. Navy ships from Hong Kong when bilateral relations have been strained.

In recent weeks, the two sides have had disagreements over trade, Iran's nuclear program and Congress's awarding a medal to the Dalai Lama, the Tibetan spiritual leader whom China's Communist government considers an enemy.

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.

The 46-year-old USS Kitty Hawk is the only U.S. aircraft carrier permanently deployed abroad.