After first extracting Latvian agreement under duress—Stalin personally threatened the Latvian foreign minister, in Moscow, during negotiations—to the stationing of Soviet troops on Latvian soil, the Soviet Union invaded Latvia on June 16, 1940. Jewish civic and political leaders began to be arrested in August 1940. The first to be arrested were the Zionist leaders Favid Varhaftig and Mahanud Alperin. The leadership of Betar were deported. In 1941, the Soviets arrested Mordechai Nurock, M. Dubin and other Jewish civic leaders, Zionists, conservatives, and right wing socialists. Their arrest orders were approved by S. Shustin. When the Soviets executed the first round of mass Baltic deportations, on the night of June 13–14, 1941, thousands of Latvian Jews were deported along with Latvians. Of all the ethnic groups so deported, Jews suffered proportionately more than any other, and were deported to especially harsh conditions. Records have been preserved of the deportations of 1,212 Jewish Latvian citizens (12.5% of those deported to the far reaches of the USSR) but the actual number of Jews deported was certainly larger, on the order of 5,000 to 6,000 during the first Soviet occupation.