China refused permission for a US aircraft carrier and accompanying vessels to visit Hong Kong for a long-planned Thanksgiving holiday visit - and then changed its mind.
The USS Kitty Hawk group and its crew of 8,000 airmen and sailors had been expected in Hong Kong on Wednesday, but the US State Department said the visit had been blocked by China.
Hundred of relatives of crew members of the Kitty Hawk had flown to Hong Kong to celebrate Thanksgiving.
Hong Kong, especially its Wanchai bar district, has been a regular port of call for US sailors on "R & R" (rest and recuperation) since the Vietnam War.
The Chinese move came as a surprise just weeks after a visit to China by US Defence Secretary Robert Gates, which he said he hoped would lead to a long-term dialogue.
But the Chinese Foreign Ministry said on Thursday the carrier would be allowed to dock in the former British colony after all.
"We have decided to allow the Kitty Hawk to stay in Hong Kong during Thanksgiving," spokesman Liu Jianchao told a news conference.
"It is a decision based on humanitarian considerations only."
He did not say why the ships had been blocked in the first place.
The issues that may have prompted Beijing's action include US plans to sell Taiwan a $US940 million ($A1.07 billion) upgrade to its missile system and last month's meeting between US President George W Bush and the Dalai Lama, the Tibetan Buddhist leader who Beijing considers a traitor.
Last year, a Chinese submarine surfaced uncomfortably close to the Kitty Hawk near the Japanese island of Okinawa, an incident that highlighted the potential for friction between the two powers.
Beijing's move coincided with "airspace controls" introduced on Wednesday which the Xinhua news agency said affected the air travel plans of 7,000 people in south and east China.
The controls had been ordered for "unspecified reasons".
The Kitty Hawk, laid down in 1956, has the second longest active service of any ship in the US navy after the USS Constitution, a 208-year-old ceremonial sailing ship kept in Boston Harbour.
It is the only conventionally fuelled carrier in the US fleet and is due to be decommissioned next year.