Prime Minister Shinzo Abe has visited a shrine honouring Japan's war dead in a move that led to China warning that already poor relations would worsen.
Thursday's visit to the shrine, which honours 2.5 million war dead including convicted Japanse war criminals, prompted Chinese Foreign Minister Wang Yi to summon Japanese Ambassador to China Masato Kitera.
"This is a grave provocation to the international justice and also ruthless trampling on human conscience," Wang said following the meeting.
Earlier, Qin Gang, a Foreign Ministry spokesman, issued a strong rebuke in a statement posted on the ministry's website.
"We strongly protest and seriously condemn the Japanese leader's acts," Qin said.
He called visits to Yasukuni an effort to glorify the Japanese militaristic history of external invasion and colonial rule and to challenge the outcome of World War II.
I have no intention to neglect the feelings of the people in China and South Korea
"Japanese leaders are not only showing no moderation but have doubled their efforts and created a serious incident on historical issues," Qin said.
"The essence of Japanese leaders' visits to the Yasukuni shrine is to beautify Japan's history of militaristic aggression and colonial rule," he added.
The visit was the first by a sitting prime minister since 2006, when Junichiro Koizumi went to the shrine marking the end of World War II.
Visits to Yasukuni by Japanese politicians have long been a point of friction with China and South Korea, because of Japan's brutal aggression during World War II.
Abe said criticism that Yasukuni visits were an act of worshipping war criminals was based on a misunderstanding.
"Unfortunately, a Yasukuni visit has largely turned into a political and diplomatic issue," he said.
"I have no intention to neglect the feelings of the people in China and South Korea."
Al Jazeera's Rob McBride, reporting from Hong Kong, said the rebuke from China was expected.
"But the strength of the language was unusually harsh," McBride said.
"Relations between the two are already at a low ebb given the current territorial dispute between China and Japan over islands in the East China Sea," he said. "Abe’s visit is likely to further escalate the rhetoric from both sides."
Anger in Seoul
Abe said relations with China and South Korea were important.
"I hope for an opportunity to explain to China and South Korea that strengthening ties would be in the national interest," Abe said.
China and South Korea have repeatedly expressed anger in the past over Japanese politicians' visits to Yasukuni Shrine, where Japanese leaders convicted as war criminals by an Allied tribunal are honoured along with war dead.
The shrine is seen in parts of Asia as a symbol of Japanese past militarism.
"We can't help deploring and expressing anger at the prime minister's visit to the Yasukuni shrine... despite concerns and warnings by neighbouring countries," Seoul's Culture Minister Yoo Jin-Ryong told reporters.
"The visit... is anachronistic behaviour that fundamentally damages not only relations between the South and Japan but also stability and cooperation in Northeast Asia."
In an interview with Al Jazeera, Victor Gao, a political analyst from Hong Kong, said by visiting the shrine, the Japanese prime minister is disregarding the atrocities Japan committed during World War II.