Buyan-class corvette  The Buyan class, (), Russian designations Project 21630 "Buyan and Project 21631 "Buyan-M, are series of corvettes (small artillery and missile ships in Russian classification) developed by Zelenodolsk Design Bureau for the Russian Navy. Since 2010, all subsequent vessels are being constructed as improved Project 21631 subclass, incorporating greater tonnage, stealth technology and the 3S-14 vertical launching system for either Kalibr or Oniks anti-ship cruise missiles, significantly enhancing combat capabilities. The ships are primarily designed for operations within littoral zones to protect Russia's vast coastal areas. Due to the small tonnage, they can operate even within shallow parts of oceans and seas and Russia's river system. The export variant is known as Project 21632 "Tornado". In August 2010, some informations about the newly modified Project 21631, dubbed as "Buyan-M", were published. The Project 21631 ships are said to be an up-to-date variant of Project 21630 "Buyan" small artillery ship, armed with the nuclear-capable Kalibr cruise missiles (SS-N-27 "Sizzler") with a claimed range of at least 1,500 km and electronic countermeasure equipment. Ships of Project 21631 are designed to defend the national economic zones of Russia. The ships' small size and displacement enable them to operate within inland river systems, including traversing the Moscow Canal which allows them to deploy to various seas around European Russia. This is a particular advantage for the "Buyan-M" series, because while the Intermediate-Range Nuclear Forces Treaty (INF) prohibits long-range cruise missiles from operating on land they can operate from ships, so a river-based corvette can deploy missiles without being subject to restrictions. The lead ship of this project, "Grad Sviyazhsk", was laid down on 27 August 2010 and commissioned on 27 July 2014. On 7 October 2015, corvettes "Grad Sviyazhsk", "Uglich", "Velikiy Ustyug" and "Dagestan", deployed in the Caspian Sea, launched 26 Kalibr cruise missiles at 11 terrorist targets in Syria. The missiles flew nearly over Iran and Iraq and struck targets in Raqqa and Aleppo provinces (controlled by the Islamic State) as well as in Idlib province (controlled by the al-Qaeda-linked Nusra Front). According to US DoD officials, several of these cruise missiles fired from Russian ships crashed in Iran and did not make it to their intended targets in Syria.