China's ambassador to Tokyo said Thursday that Chinese President Xi Jinping's official visit to Japan as a state guest, if realized, would be "invaluable" for bilateral relations that have often been strained over issues that include a territorial row.

In an interview with Kyodo News, Kong Xuanyou also stressed that China must continue to emphasize "leader-level" exchanges with Japan, weeks after the two Asian powers held their first summit in almost three years.

Kong's remarks came as protests against China's "COVID-zero" policy, involving lockdowns and quarantines under strict public surveillance, have been spreading at home, with some demonstrators making an extremely rare demand for Xi to step down.