Japan's top government spokesman has acknowledged that Prime Minister Shinzo Abe earlier this year sent a note to a temple ceremony honoring hundreds of World War II-era war criminals that praised their contributions to the country.

Chief Cabinet Secretary Yoshihide Suga said Wednesday that Abe send the note to a ceremony held April 29 at the Koyasan temple in central Japan, but in his capacity as head of the ruling party, not as prime minister.

Suga was responding to a newspaper report that Abe's message, which was read out loud at the ceremony, said the war criminals "sacrificed their souls to become the foundation of their country."

The revelation could worsen Japan's ties with China, which sees honoring war criminals as a lack of remorse by Tokyo over wartime aggression.