WASHINGTON, May 11 (AFP) - US National Security Advisor Jake Sullivan and top Chinese diplomat Wang Yi met in Vienna this week, Washington and Beijing announced on Thursday (May 11), as the two powers seek to maintain communication amid soaring tensions, especially over Taiwan.

The two held eight hours of talks stretching over Wednesday and Thursday in the Austrian capital, ending an unofficial pause in high-level contacts since the United States shot down a Chinese surveillance balloon that had travelled across the country in January and February.

Both sides described the previously unannounced meeting as "candid, substantive and constructive", covering topics including the Russian invasion of Ukraine and Taiwan, according to the White House - two of the most sensitive subjects in the frosty relationship between the world's top two economies.

Washington has repeatedly warned China against offering any military assistance to Russia, and is closely watching its moves over Taiwan - which Beijing claims as its own territory.

The self-ruled island lives under the constant fear of a Chinese invasion, and Beijing has stepped up its rhetoric and military activity around it in recent years.

Wang "comprehensively expounded upon China's solemn position" on Taiwan, Chinese state-run news agency Xinhua said, adding the two diplomats "agreed to continue to make good use of this strategic channel for communication".