The South Korean government expressed deep regret on Thursday over Japanese Prime Minister Shinzo Abe's decision earlier in the day to send a ritual offering to Tokyo's controversial Yasukuni Shrine.
Japan's Chief Cabinet Secretary Yoshihide Suga said Abe made the offering in his capacity as a private citizen, but did not visit the shrine in person.
It's the seventh straight year Abe has sent offerings to mark the country's 1945 surrender in World War Two.
About 50 right-wing lawmakers from ruling and opposition parties also paid their respect at the shrine.
The shrine honors Japan's war dead including 14 Class-A war criminals.
For Korea and China, it's regarded as a symbol of Japan's past imperialism.