China urged the United States to sack the head of the U.S. Pacific Command in return for exerting more pressure on North Korea amid concerns over its growing nuclear and missile threats, a source close to U.S.-China ties said Saturday.

The Chinese leadership headed by President Xi Jinping made the request, through its ambassador in the United States, to dismiss Adm. Harry Harris, known as a hard-liner on China, including with respect to the South China Sea issue, the source said.

China's envoy to the United States, Cui Tiankai, conveyed the request to the U.S. side, to coincide with the first face-to-face, two-day meeting between President Donald Trump and Xi in Florida from April 6, but the Trump administration likely rejected it, the source said.