Prime Minister Junichiro Koizumi observed the 60th anniversary of Japan's defeat in World War II on Monday by apologizing for the country's past militarism in Asia and pledging to uphold its postwar pacifism.

In a speech at a government-sponsored memorial service at the Nippon Budokan hall here, Mr. Koizumi also reached out directly to China and South Korea by saying that the three nations should work together "in maintaining peace and aiming at development in the region."

Mr. Koizumi joined Emperor Akihito, who said he hoped that "the horrors of war will never be repeated," in bowing before an altar of chrysanthemums. Exactly sixty years ago, the emperor's father, Emperor Hirohito, spoke directly to the Japanese people for the first time when he announced Japan's surrender over the radio, saying they should "bear the unbearable and endure the unendurable."

In the first apology delivered on Aug. 15 by a prime minister since the 50th anniversary of the war's end, Mr. Koizumi said: "Our country has caused tremendous damage and pain to the peoples of many countries, especially Asian countries, through colonial rule and invasion. Humbly acknowledging such facts of history, I once again reflect most deeply and offer apologies from my heart."