TOKYO — Japan announced a new defense policy on Friday that will respond to China’s rising military might by building more submarines and other mobile forces capable of defending Japan’s southernmost islands.

The new National Defense Program Guidelines are the biggest step yet in a decade-long shift away from cold war-era deployments of heavy tank and artillery units on the northern island of Hokkaido — to counter a now-vanished Soviet threat — and toward bolstering Japanese forces in the southern islands around Okinawa, where China’s navy has become a growing presence.

The new guidelines also used uncharacteristically strong language to warn of China’s rapidly modernizing military, calling it “a matter of concern for the region and the international community.” China’s growing naval capabilities have been a particular concern in Japan since Beijing and Tokyo clashed diplomatically three months ago over uninhabited islands claimed by both nations but controlled by Japan. The islands are called the Senkaku in Japanese and Diaoyu in Chinese.

In Beijing, the Foreign Ministry criticized the new policy as “irresponsible” and suggested that it was based on a misunderstanding of China’s intentions. “China adheres to the road of peaceful development and pursues a defensive national defense policy,” Jiang Yu, the Foreign Ministry spokeswoman, said in a statement. “We have no intention to be a threat to anyone.”