China's top admiral visits United States

China's top naval official left Beijing for a visit to the United States on Sunday, a move experts described as part of the "rare, determined and intensive efforts" by Beijing and Washington in recent months to improve military ties.

The trip coincides with a joint China-US naval drill, involving three Chinese warships, scheduled on Monday in waters off Hawaii.

Wu Shengli, commander-in-chief of the People's Liberation Army navy, will pay an official visit at the invitation of Chief of US Naval Operations Admiral Jon Greenert, the Chinese navy said in a news release on Sunday.

His tour comes three weeks after Minister of National Defense Chang Wanquan visited the US.

"During the visit, Wu Shengli will meet leaders of the US navy and discuss issues including building up a new type of China-US naval relations and constructively pushing up relations between Chinese and US navies," said the document. Wu will also visit US naval and marine units, it said.

Meanwhile, speaking at Washington-based think tank American Enterprise Institute on Thursday morning, Greenert said he is looking forward to meeting Wu as "we continue our mil-to-mil relationship, evolving and maturing that relationship".

Niu Jun, professor at the School of International Studies of Peking University, said: "I have spent years studying China-US relations. It is very rare to see the determined efforts made by both sides, after the two new administrations took office, to improve the relations."

"And progress in military ties is the most eye-catching and symbolic part in bilateral relations. That is partially because it is the sphere with most problems," Niu said.

Shortly before Wu's arrival, three Chinese navy ships pulled into Pearl Harbor in Hawaii on Friday for a search-and-rescue exercise with the US navy.

The three ships — destroyer Qingdao, frigate Linyi, and fleet oiler Hongzehu — carry a helicopter and 680 officers and sailors. They were greeted in Hawaii with a lion dance from a children's group.

The drill is scheduled on Monday with USS Lake Erie in waters off Waikiki and Diamond Head.

"This port visit is part of the US navy's ongoing efforts to maximize opportunities for developing relationships with foreign navies as a tool to build trust, encourage multilateral cooperation, enhance transparency, and avoid miscalculation in the Pacific," the US Navy said in a news release.

It was the first such port visit by the Chinese navy in the past seven years, since Qingdao and Hongzehu stopped at Pearl Harbor and San Diego for communications drills and search-and-rescue exercises off the coasts.