China warned students planning to study in Japan of heightened risks for Chinese citizens in the country as a diplomatic spat sparked by Japanese Prime Minister Sanae Takaichi’s comments on Taiwan shows no sign of easing.

Both countries have summoned each other’s ambassadors after Prime Minister Sanae Takaichi said a Chinese attack on Taiwan could draw a military response from Tokyo.

BEIJING (Reuters) -A China Coast Guard ship formation passed through the waters of the Senkaku Islands on Sunday on a "rights enforcement patrol", the China Coast Guard said in a statement, as Beijing ramps up tensions with Japan over its prime minister's remarks on Taiwan.

The release of the results of an opinion poll conducted in China and Japan has been abruptly postponed by the Chinese side.

Analysts say more ‘quasi-security alliances’ between US allies in the region could form an ‘effective security network’ targeting Beijing.

A diplomatic row between China and Japan is stirring up old maritime tensions. China has sent a coast guard ship formation through islands that are claimed by both Beijing and Tokyo. The patrol comes as a spat deepens over remarks from Japan’s prime minister about possible military action if China attacked Taiwan.

Prime Minister Sanae Takaichi said a Chinese attack on Taiwan could constitute “a survival-threatening situation” for Japan, drawing sharp criticisms from Beijing.

A Chinese diplomat’s call to cut off the prime minister’s “filthy head” signaled a revival of a combative style Beijing had tried to dial back.