China's President Xi Jinping struck a friendly tone on relations with Japan Saturday, but touched on disputes over history which still add to tensions between the East Asian giants.

Ties between Beijing and Tokyo have warmed over the past year, but strains over territorial disputes and attitudes towards wartime history persist.

Xi told a forum in Beijing that "peace and friendly cooperation between China and Japan is the common will of the people, and the general trend of events".

He added that "friendship" between the countries "deserves cherishing and protecting," at the event, attended by Japanese delegates including former economy minister Toshihiro Nikai.

High-level meetings between China and Japan were suspended for two years amid a row over disputed islands until Xi and Japan's Prime Minister Shinzo Abe met last year. They held talks again last month.

During his Beijing visit, Nikai delivered a personal letter to Xi from Abe, Japan's Kyodo news agency said, without giving further details.

Echoing regular pronouncements from Beijing, Xi also mentioned the 70th anniversary of the Japanese surrender in the second world war, and added that "the facts of history cannot be distorted".

"The efforts of anyone seeking to distort or beautify the facts of Japan's acts of militaristic invasion will not be accepted by the people of China," he added.

His remarks came just a day after China renewed its call for Japan to "face up to" its 20th century history after Abe's wife visited a shrine which Beijing sees as a symbol of Tokyo's warring past.

China is preparing a massive military parade in September to mark the 70th anniversary, and also creating a public holiday.

China's defence ministry said that its army planes on Thursday for the first time flew over the Miyako Strait, between Japan's Miyako and Okinawa Islands.