Turkey, which is hosting a 22-nation security summit, is seeking international condemnation for the May 31 raid on a Turkish ship that killed nine pro-Palestinian activists.
Israel says its soldiers began shooting only after a mob of activists attacked them.
Russian Prime Minister Vladimir Putin said Tuesday "we condemn this act," and expressed concern that it was conducted in international waters. He was speaking at a news conference with Turkish Prime Minister Recep Tayyip Erdogan.
A Turkish government official said Israel was trying to block an attempt by Turkey to insert a strong condemnation of Israel into a joint summit statement.
