Two bombs blamed on leftist radicals blew up in a police dormitory, killing an officer and injuring six other people. The blasts and other incidents Friday cast doubt on security efforts for Emperor Akihito's coronation 10 days away.

Three unexploded bombs were found and a firebomb was hurled at a police station Friday, after the blasts at the dormitory early this morning and late Thursday night.The violence occurred as 26,000 police officers were mounting a massive security operation for the Tuesday coronation. Representatives from more than 150 countries are to attend, including Vice President Dan Quayle and Britain's Prince Charles.