TAIPEI (Taiwan News) — Chinese coast guard vessels entered territorial waters around the Diaoyutai Islands on Sunday, marking the latest flare-up in tensions between Beijing and Tokyo following comments by Japan’s prime minister about Taiwan, per CNA.

China, Japan, and Taiwan each claim sovereignty over the uninhabited island chain, known as the Senkaku Islands in Japanese. China's coast guard said on its WeChat account that Vessel 1307 and accompanying ships conducted a “lawful patrol” within what it called “our Diaoyu Islands.”

The patrol comes after Japanese Prime Minister Takaichi Sanae told parliament on Nov. 7 that a Chinese attack on Taiwan could trigger a military response from Japan. Beijing sharply criticized the remarks, which it views as touching on core national interests.

Tensions over the islands have periodically strained relations, including during the administration of former Japanese Prime Minister Abe Shinzo. 

This latest dispute has quickly escalated. China’s consul general in Osaka issued inflammatory comments last week about Japan’s position on Taiwan, prompting a formal protest from Tokyo.

Beijing later summoned Japan’s ambassador for the first time in more than two years, and China’s defense ministry warned that any Japanese involvement "would be doomed to fail," according to Reuters.

Alongside the coast guard patrols, China’s Maritime Safety Administration announced three days of live-fire exercises in parts of the Yellow Sea beginning Monday. It issued a navigation warning prohibiting entry into designated zones.