Russian President Vladimir Putin fired the head of the Russian navy in an attempt to boost discipline in the fleet following recent submarine disasters.
Mr Putin did not give a specific reason for sacking Adm Vladimir Kuroyedov and replacing him with Adm Vladimir Masorin, but he indicated Adm Kuroyedov was bearing the blame for a series of embarrassments in the navy.
Last month, a mini-sub with seven men aboard was trapped at the bottom of the Pacific Ocean. The navy had no means of rescuing them without emergency help from abroad.
Adm Kuroyedov also presided over the Navy during the 2000 Kursk submarine sinking that killed 118 crew members. Last year, he said a Russian nuclear-powered missile cruiser was in such dire condition it could explode at any moment. He was forced to retract the statement.
At a meeting with the two admirals and Russian Defence Minister Sergei Ivanov, Mr Putin told Adm Kuroyedov the navy he inherited in 1997 was in poor shape and that it had showed signs of improvement.
"At the same time, there were difficult events, tragedies," Mr Putin said during the meeting.
He told Adm Masorin that he faced a difficult task, in spite of progress.
AP