Japan has accused China of "disinformation" about the coronavirus and expressed "deep concern" about its claims in the South China Sea and the disputed Senkaku islands.
Diplomatic relations between Tokyo and Beijing, which had been warming up since the end of 2018, have cooled again in recent months, against a backdrop of dissatisfaction on the part of many countries with China's handling of the coronavirus crisis and the international outcry over the security law imposed on Hong Kong.
In its annual white paper on its defence policy published on Tuesday, Japan blamed China for "propaganda" and "disinformation" about the coronavirus, which first appeared at the end of 2019 in the Wuhan metropolis in the centre of the country.
Japan cited as an example the comments on Twitter of a Chinese Foreign Ministry spokesman who suggested in March that Covid-19 had been introduced into Wuhan by the US military, or the promotion of Chinese herbal medicines to treat the disease.
Beijing has also "relentlessly continued its unilateral actions to impose a change in the status quo on the Senkaku Islands", administered by Tokyo.
The two countries have long claimed their respective sovereignty over this uninhabited micro-archipelago in the East China Sea, called Diaoyu by Beijing, whose seabed is said to be potentially rich in hydrocarbons.
On Monday, the head of US diplomacy Mike Pompeo said Beijing's claims to offshore resources in the South China Sea were "completely illegal, as is its campaign of intimidation to control them".
The Chinese embassy in the United States immediately denounced "totally unjustified accusations".
Japan's defence white paper also mentioned the continuing North Korean threat, pointing out that Pyongyang is now capable of miniaturizing nuclear warheads for use in ballistic missiles.