The Baltic states acceded to the Soviet demands and signed mutual assistance treaties on September 28, October 5, and October 10, 1939, respectively (for ten years for Estonia and Latvia and fifteen years for Lithuania). The tension included the internment of a submarine crew in the Orzeł incident. On October 18, October 29, and November 3, 1939, the first Soviet troops entered Estonia, Latvia, and Lithuania under the Pact.[128][129][130]