TOKYO - Embattled Japanese Prime Minister Yukio Hatoyama said today he was resigning over his broken campaign promise to move a U.S. Marine base off the southern island of Okinawa.

The prime minister had faced growing pressure from within his own party. His approval ratings had plummeted over his bungled handling of the relocation of the Marine Air Station Futenma, reinforcing his public image as an indecisive leader.

Hatoyama is the fourth Japanese prime minister to resign in four years.