Chinese ambassador to US to step down after eight years

China's long-serving ambassador to Washington, Cui Tiankai, confirmed on Tuesday that he is leaving his post.

Cui, who is 68 and past the retirement age of 65 for Chinese diplomats of his level, has been in the post for eight years and leaves amid ongoing tensions between Washington and Beijing.

"I will forever treasure the deep friendship forged with the Chinese nationals here during my posting in the United States," he wrote in a farewell letter posted on the embassy's website.