China has accused Japan of threatening regional peace after Tokyo passed laws clearing Japanese troops to fight abroad for the first time since World War II, saying that its rival should learn "profound lessons from history".
Japan's ruling coalition, led by nationalist Prime Minister Shinzo Abe, pushed the laws through in the early hours of Saturday morning after days of tortuous debate that at times descended into physical scuffles in parliament.
For the first time in 70 years, the new laws will give the government the power to send the military into overseas conflicts to defend allies, even if Japan itself is not under attack.
China's defence ministry said on Saturday the reforms had "aroused grave concern among its own citizens, Asian neighbouring countries and the international society," state media reported.
A Xinhua editorial added that Japan's new security bills "not only broke Japan's promise to the world after World War II, but also betrayed its own people".
Japan's nationalist premier has argued the laws are necessary to protect against threats from what it views as an increasingly belligerent China and unstable North Korea, but opponents fear the vague wording could see Japan dragged into far-flung foreign wars.
South Korea called on Japan to remember the need for transparency in implementing its new defence policy "while maintaining the spirit of the pacifist constitution," its foreign ministry said in a statement cited by the Yonhap news agency.
North Korea's official KCNA news agency later released a strongly-worded statement from the foreign ministry accusing Japan of being "obsessed with an anachronistic ambition for reinvasion".
"Japan's militarist moves are posing a grave threat to peace and stability in Asia and the rest of the world," the statement added.
It warned the North "will further increase the war deterrence to cope with the dangerous moves for aggression against it".