HONG KONG A U.S. aircraft carrier Battle Group steamed into Hong Kong on Monday, the most significant U.S. military presence allowed into Chinese territory since Washington and Beijing began mending fences after a deadly spy-plane incident in April.

But in a sign China still remains wary about U.S. airpower, Reuters quoted the official Xinhua news agency as saying on Sunday that Beijing had recently refused permission for a long-range U.S. reconnaissance plane to stop in the territory.

The carrier USS Constellation, accompanied by a frigate, two destroyers, a nuclear submarine and another vessel, anchored northwest of Hong Kong island on a six-day port call.

The Constellation and another carrier Battle Group led by the USS Carl Vinson conducted military exercises in the South China Sea on Friday.

Some defense analysts saw the one-day exercise as a show of U.S. military might in support of Taiwan during large-scale Chinese military exercises in the Taiwan Strait. China considers Taiwan a renegade province.

But Rear Admiral Terrance Etnyre played down its significance at a media briefing in Hong Kong, saying having both battle groups in the same area was a good chance for a joint exercise. The Constellation was returning from Singapore while the Vinson was on its way to the Middle East.

Sino-U.S. relations are normalizing after an acrimonious row triggered by the mid-air collision between a U.S. spy plane and a Chinese fighter in April.

The U.S. consulate in Hong Kong said on Monday that the U.S. military plane that had been denied permission to stop in Hong Kong recently was a P-3C Orion. The Maritime Patrol aircraft, which is used for antisubmarine operations, is similar to the EP-3 spy plane involved in the collision.

China denied permission for a U.S. minesweeper to make a port call in Hong Kong in May but has since granted permission for two other minesweepers to visit in late July.

Hong Kong returned to Chinese rule in 1997.

Constellation's arrival is an economic boon to Hong Kong's flagging retail industry.

"I just want to take a long, long bath, then do some sightseeing and some shopping", said Joseph Rey Quiroz, a public relations staffer on the aircraft carrier.

American sailors spend an average of U.S.$100 to U.S.$300 a day while in Hong Kong on shopping and entertainment.