Japanese Prime Minister Shinzo Abe sent an offering to a controversial war shrine on Friday as 100 lawmakers paid their respects there in a move Beijing said ratcheted up regional tensions.
A cross-party group of parliamentarians said 110 members paid homage at Yasukuni Shrine in downtown Tokyo, a spot condemned by China and Korea as a symbol of Japan's militarist past.
The visit coincided with the start of the shrine's four-day autumn festival.
Abe, who offered a potted tree with his name and title prominently displayed, is thought unlikely to go even after he returns home Saturday from an Asia-Europe summit in Italy.
His visit in December last year infuriated Beijing and Seoul, who say the inclusion of senior war criminals among those honoured by the shrine makes it an insult to the grievous injuries Tokyo inflicted up to and during World War II.
China reacted with renewed anger on Friday.
"China is gravely concerned and firmly opposes the negative activities in Japan surrounding the Yasukuni Shrine," foreign ministry spokesman Hong Lei said in a statement.
"China would like to reiterate that Sino-Japan relations can only realise healthy and stable development when Japan seriously faces up to and repents of its aggressive past and disassociates itself with militarism," he added.
Taiwan, a Japanese colony until 1945, also offered a rebuke, saying visits hurt "people's feelings in neighbouring countries."
"We... urge the Japanese government and politicians to face history and deeply reflect to take constructive actions... to jointly create the prospect of peace and prosperity," the foreign ministry said in a statement.
The 145-year-old Shinto shrine honours some 2.5 million citizens and soldiers who died in World War II and other conflicts.
They include senior figures in the WWII administration, such as General Hideki Tojo, who ordered the attack on Pearl Harbor.
Nationalist politicians who go to the shrine feign innocence and claim there is nothing wrong with honouring war dead.
Hidehisa Otsuji, who led the group of lawmakers, said it was only "natural" that they visit the shrine to offer gratitude to the people who sacrificed their lives for the nation.
"People in any country pay homage to those who died for the sake of their countries," he told reporters at the shrine.
"It is odd that Japanese people are told off over doing what is also practised in any country" in the world, he said.
The group visited Yasukuni during its spring and autumn festivals as well as on the August 15 anniversary of Japan's surrender in World War II.
Each time they do, it provokes a rebuke from China and South Korea.
No ministers in Abe's current government were seen at the shrine Friday.
Health, labour and welfare minister Yasuhisa Shiozaki sent a tree offering, like Abe.
Japan's top government spokesman Yoshihide Suga declined to comment on the prime minister's offering, saying it was done in his capacity as "a private citizen".
Suga also said Abe and his cabinet would make their decisions on visiting the shrine independent of any other considerations, and insisted the ministerial no-show was not linked to to an upcoming international meeting in Beijing.
The prime minister is pushing for a summit with Chinese President Xi Jinping on the sidelines of APEC next month.
He stayed away from Yasukuni this year, although he made offerings for the spring festival and on the war anniversary on August 15.
His visit in December 2013 drew not only anger from neighbours, but a diplomatic ticking off from the United States, a key ally, which said it was "disappointed" by the decision.