SEOUL (Reuters) - South Korea on Sunday protested Japanese Prime Minister Fumio Kishida's offering to Tokyo's Yasukuni Shrine with "deep disappointment" and urged Japanese leaders to show repentance for the country's wartime past.

The shrine is seen by Beijing and Seoul as a symbol of Japan's past military aggression because it includes 14 Japanese wartime leaders convicted as war criminals by an Allied tribunal among the 2.5 million war dead honoured there.

Past offerings there by Japanese leaders have led to protests from the two countries.

Kishida and some cabinet members sent ritual offerings to the shrine on Sunday, Yonhap news agency reported, citing Japanese media.

"The government expresses deep disappointment and regret that Japanese leaders again sent offerings to or visited the Yasukuni shrine which glorifies Japan's war of aggression and enshrines war criminals," South Korea's foreign ministry said.

South Korea's urges Japanese leaders to "face history squarely and demonstrate humble reflection and sincere repentance" which would be an important foundation for improved ties between the two countries, it said in a statement.

It did not mention Kishida by name.

Japanese foreign ministry officials could not be immediately reached for comment.

The two countries have moved closer in ties after South Korean President Yoon Suk Yeol made it a foreign policy priority to improve security cooperation with Tokyo and Washington since taking office in 2022.

Last week, the finance ministers of the two countries also joined U.S. Treasury Secretary Janet Yellen for the first trilateral meeting by top financial officials.

(Reporting by Jack Kim in Seoul and Kevin Buckland in Tokyo; Editing by Lincoln Feast.)