A Japanese minister and more than 100 other lawmakers visited the Yasukuni Shrine for war dead on Friday, prompting China to accuse Japan of undermining ties and trying to overturn the post-World War Two order.
China summoned Tokyo's ambassador in Beijing to express its anger and South Korea also criticized the lawmakers' action.
The visits, marking an autumn festival, came a day after Japanese Prime Minister Shinzo Abe made his third ritual offering to the shrine since returning to office last year, though he did not visit it in person.
Abe has stayed away from the shrine in central Tokyo, where war criminals are honored along with other war dead, to avoid further straining ties with China and South Korea, both victims of Japan's militarism before its surrender in 1945.
"The Yasukuni Shrine is a symbol and spiritual tool of Japanese militarism," Chinese Foreign Ministry spokeswoman Hua Chunying told a news conference in Beijing.
"It consecrates monstrous crimes committed against Asia's victimized peoples, including those in China, by 14 Class A war criminals... This is a major matter of principle bearing on the foundation of Sino-Japanese relations."
The visits, she said, were another attempt to whitewash Japan's history "and challenge the end result of World War Two, as well as the post-war international order."
China's Vice Foreign Minister Liu Zhenmin summoned Masato Kitera, Japan's ambassador to China, to "lodge solemn representations" over the visits, said Hua.
As well as Japan's war dead, Yasukuni also honors Japanese leaders convicted as war criminals by an Allied tribunal, making it a painful reminder to nations that suffered from Japanese aggression in the 20th century.
Internal Affairs Minister Yoshitaka Shindo was the most senior of about 160 lawmakers to visit the shrine to mark the festival, which runs until Sunday. A deputy chief cabinet secretary also went.
"I visited the shrine in a private capacity," Shindo said, noting that his grandfather is honored there. "I do not think this should become a diplomatic issue."
Sino-Japanese ties have been overshadowed for years by what China says has been Japan's refusal to admit to atrocities committed by Japanese soldiers in China between 1931 and 1945.
Memories of a brutal Japanese occupation also remain strong in South Korea, where the Foreign Ministry repeated its view that Japanese lawmakers should stay away from the shrine.
"We urge Japanese politicians to show speech and actions based on humble introspection and reflection of the past that will help build trust with its neighboring countries," the South Korean ministry said in a statement.
Japan's deputy chief cabinet secretary Katsunobu Kato said he had also visited the shrine in a private capacity.
"I think that it's only natural to pray for the repose of the souls of people who have given their precious lives for the nation," Kato told a news conference.
Ties between Tokyo and Beijing have been fraught for months because of a territorial dispute over islets in the East China Sea, known as the Senkaku in Japan and the Diaoyu in China.
Japan's relations with South Korea have cooled over a separate territorial dispute.
Abe is seen as a hawkish nationalist with a conservative agenda that includes revising the post-war pacifist constitution, strengthening Japan's defense posture and recasting wartime history with a less apologetic tone.
He has said he regretted not visiting the shrine when he was prime minister in 2006-2007.