By Francis Markus BBC Shanghai correspondent

A US warship has docked at the port of Qingdao on the first visit to mainland China by an American navy ship since the crisis triggered by the collision of a US spy plane and a Chinese fighter in April last year.

The port call marks the resumption of military ties between the two countries.

The US spy plane row severely strained ties

A US battle group has also been visiting Hong Kong on its way to the Middle East.

As the American destroyer, the USS Paul F Foster, pulled into the eastern port it was welcomed by a Chinese military band and a little girl holding a bouquet of flowers.

Its arrival marked the most visible symbol of a relationship which US officials describe as "on a roll" following President Jiang Zemin's summit with his US counterpart, George W Bush, in Texas last month.

Spy plane row

Military ties are being restored after the crisis triggered by last year's collision of a US naval spy plane and a Chinese fighter jet, with high-level military exchanges expected over the next few weeks.

Bush hosted Zemin in the US last month

The common security interests highlighted by the 11 September, 2001, attacks on the United States have been the most important factor in changing the atmosphere.

There remains mutual suspicion in some quarters, both in Washington and in Beijing, though, despite the prevailing mood.

There is no shortage of issues such as trade and human rights and, the most serious, US support for Taiwan. Beijing also remains wary of possible US military action against Iraq.

But for the moment it is a relationship which seems back on track.

American officials are privately relieved that despite the leadership changes at China's recent Communist Party Congress, there is every sign that Jiang Zemin, with whom they are relatively familiar, will play an influential role in Chinese politics for some time to come.