MOSCOW, July 12. /TASS/. The Project 21631 corvette Stavropol armed with Kalibr cruise missiles was laid down at the Zelenodolsk Shipyard in the Volga Republic of Tatarstan, the press office of Russia’s Defense Ministry reported on Thursday."Today the Project 21631 small missile ship Stavropol was laid down at the Zelenodolsk Shipyard," the press office said.The keel-laying ceremony was attended by Russian Deputy Defense Minister Alexei Krivoruchko, representatives of the Navy’s Main Command and the Tatarstan authorities.The Stavropol is the 12th Project 21631 corvette laid down at the Zelenodolsk Shipyard. Six such warships are already operational in the Russian Navy. The warships of this class are armed with Kalibr cruise missiles designated to hit sea and coastal targets, and is also furnished with the Pantsyr-M air defense missile system and artillery guns.