 According to Benjamin Valentino, probably tens or hundreds of thousands of deaths occurred as part of political repression and agricultural collectivization in Communist Romania, though he said documentation is insufficient for an accurate estimate to be made.Gheorghiu-Dej attained greater independence for Romania from the Soviet Union by persuading Soviet First Secretary Nikita Khrushchev to withdraw troops from Romania in April 1958.After the negotiated withdrawal of Soviet troops, Romania under the new leadership of Nicolae Ceauşescu started to pursue independent policies, including the condemnation of the Soviet-led 1968 invasion of Czechoslovakia—Romania being the only Warsaw Pact country not to take part in the invasion—the continuation of diplomatic relations with Israel after the Six-Day War of 1967 (again, the only Warsaw Pact country to do so), and the establishment of economic (1963) and diplomatic (1967) relations with West Germany.