On Saturday, Vladimir Putin held a meeting with Vladimir Ustinov, Russian Prosecutor General. According to the presidential press office, President was reported on the preliminary results of investigation into causes of the nuclear submarine Kursk catastrophe. After that, the president had a meeting with defense minister Sergei Ivanov, Chief of General Staff Anatoly Kvashnin, Navy Commander-in-Chief Vladimir Kuroyedov and Prosecutor General Vladimir Ustinov. At the beginning of the meeting the President said: "You have got acquainted with preliminary results of the effort of the Prosecutor General's Office to investigate into causes of the Kursk tragedy. I would like to emphasize that these conclusions are of a preliminary character and for the time being they do not give answers to the question of what had really happened." All versions continue being studied, including a version of the collision of our submarine with an unidentified underwater object".