BEIJING • Failure to properly handle sensitive issues between the United States and China could "very likely disturb and undermine" their military-to-military relations, a top Chinese official told US National Security Adviser Susan Rice.

Ms Rice is the highest-level US official to visit Beijing since an international tribunal this month rejected China's claims in the South China Sea - infuriating Beijing and fuelling tensions with Washington.

In recent months, Washington has sent naval vessels close to reefs and outcrops claimed by Beijing to assert the principle of freedom of navigation, sparking anger in China, which has built a series of artificial islands capable of supporting military operations.

Despite tensions, the two countries have tried to improve communication between their militaries in hopes of minimising misunderstandings that could lead to conflict.

"We're still faced with obstacles and challenges," Mr Fan Changlong, vice-chairman of China's Central Military Commission, told Ms Rice yesterday, adding that military ties had been "impacted by some complicated and some sensitive factors".

"If we do not properly handle these factors it will very likely disturb and undermine this steady momentum of our military-to-military relationship," he warned.

Ms Rice, whose four-day trip is intended to prepare for a visit by US President Barack Obama to a G-20 summit in Hangzhou in September, noted that "risks of unintended consequences" of the two countries' forces operating in closer proximity had been reduced thanks to better communication and other confidence-building measures.

But despite progress, "we have challenges and differences to discuss and to manage", she said.

President Xi Jinping sounded a similar conciliatory note in his meeting with Ms Rice yesterday.

While he called on both countries to effectively handle differences and respect each other's interests, he said their common interests outweighed their differences.

AGENCE FRANCE-PRESSE, XINHUA