Tokyo ? After just eight months in office, embattled Japanese Prime Minister Yukio Hatoyama said Wednesday he was resigning over his broken campaign promise to move a U.S. Marine base off the southern island of Okinawa.

The prime minister faced growing pressure from within his own party to step down ahead of July’s upper house elections. His approval ratings had plummeted over his bungled handling of the relocation of the Marine Air Station Futenma, which reinforced his public image as an indecisive leader.

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

Until Tuesday night, Hatoyama insisted he would stay on while intermittently holding talks with key members of his Democratic Party of Japan. But this morning, Hatoyama faced the nation to say he was stepping down.