Japan has officially marked the day it regained sovereignty 61 years ago following its World War II defeat, as Prime Minister Shinzo Abe's government steps up its nationalist campaign.

Abe is shifting to a more conservative agenda from economic policy. Sunday's event is seen as a step to drum up support for revising Japan's U.S.-inspired pacifist constitution.

During Sunday's ceremony, Abe pledged to make Japan a stronger country with national pride.

Visits by several ministers and nearly 170 lawmakers to Tokyo's war shrine this month have enraged China and South Korea. Abe's remarks perceived as whitewashing Japan's wartime aggression further infuriated those countries.

Abes' conservative party also pushes for recognizing Japan's defense troops as national military and for revising school texts to be less apologetic to Japan's wartime atrocities.