On 14 June 1940 the Soviets issued an ultimatum to Lithuania . The Soviet military blockade of Estonia went into effect while the world 's attention was focused on the fall of Paris to Nazi Germany . Two Soviet bombers downed the Finnish passenger airplane " Kaleva " flying from Tallinn to Helsinki carrying three diplomatic pouches from the U.S. legations in Tallinn , Riga and Helsinki . The US Foreign Service employee Henry W. Antheil Jr. was killed in the crash
Kaleva
Kaleva (airplane)
Soviet annexation of the Baltic states (1940)