The Submarine Incident off Kola Peninsula was a collision between the US Navy nuclear attack submarine USS Grayling and the Russian Navy nuclear ballistic missile submarine K-407 Novomoskovsk some 100 miles north of the Russian naval base of Severomorsk, on 20 March 1993. The incident took place when the US unit, who was trailing her Russian counterpart, lost track of Novomoskovsk. At the time that Grayling reacquired the other submarine, the short distance of only half mile made the ramming unavoidable. The incident happened just a week before the first summit between American president Bill Clinton and the president of the Russian Federation, Boris Yeltsin.