TOKYO (Kyodo) -- Japanese Prime Minister Shigeru Ishiba has emphasized the importance of U.S. involvement in achieving peace in Ukraine, which has been at war with Russia for more than three years, the Foreign Ministry said late Saturday.

In a written message to a virtual summit involving Ukraine and European nations hosted by Britain earlier that day, Ishiba also said, "We can never tolerate unilateral attempts to change the status quo by force like Russia's aggression against Ukraine anywhere in the world."

Ishiba added in the message released by the ministry, "Currently, various diplomatic efforts by countries including Europe and the United States are tirelessly ongoing to achieve a just and lasting peace in Ukraine. Japan welcomes these efforts."

Ukraine recently expressed its readiness to accept a U.S. proposal for a 30-day cease-fire with Russia, while the administration of President Donald Trump has urged Moscow to sit down for negotiations to halt the fighting.

Ishiba has pledged to continue assistance for Ukraine's reconstruction, with Japan restricted to providing nonmilitary aid under its war-renouncing Constitution.