Fan Changlong

Senior military official Fan Changlong left Beijing for the United States on Monday, the highest-level visit by a Chinese military leader to the country since China's leadership transition in 2012.

Fan, vice-chairman of the Central Military Commission, is leading a delegation that includes several generals, and he will also visit Cuba, the Ministry of National Defense said in a statement.

The visit comes amid a war of words between Beijing and Washington over China's construction on the Nansha Islands in the South China Sea, and ahead of President Xi Jinping's state visit to the US in September.

As part of his travels, Fan will visit a Boeing factory, three military bases and the aircraft carrier Ronald Reagan, according to US media outlet Defense News.

The issue of the islands will be a major topic of discussion between Fan and US Defense Secretary Ashton Carter when they meet in Washington, it quoted a US defense official as saying.

The military relationship between the world's two largest economies has improved, with increasing exchanges and exercises, and agreements to reduce risks of naval and air military encounters.

But ties have been overshadowed by contentious issues including territorial rows over the East and South China seas, cybersecurity and the Taiwan question.

Carter has recently said China's construction in the sea is outstripping the others and undermining security in the Asia-Pacific.

Fan was firm in his comments to US Secretary of State John Kerry when they met in May, saying China's construction activity is within its rights of sovereignty, and its determination to safeguard sovereignty and territorial integrity is "unswerving".

Wen Bing, a researcher at the People's Liberation Army Academy of Military Science, said the visit is a key opportunity to push forward military-to-military cooperation.

The most important task now is to strengthen consensus, Wen said, adding that an objective and pragmatic stance would allow them to resolve differences and seek greater cooperation.

OuYang Yujing, director-general of the Foreign Ministry's Department of Boundary and Ocean Affairs, said in May that China's construction and maintenance of facilities on the islands will "facilitate joint response to challenges at sea and increase navigation safety".