A series of meetings in August and September 1986 culminated in the Reykjavík Summit between Reagan and Gorbachev on 11 and 12 October 1986. Both agreed in principle to remove INF systems from Europe and to equal global limits of 100 INF missile warheads. Gorbachev also proposed deeper and more fundamental changes in the strategic relationship. More detailed negotiations extended throughout 1987, aided by the decision of West German Chancellor Helmut Kohl in August to unilaterally remove the joint US-West German Pershing 1a systems. Initially, Kohl had opposed the total elimination of the Pershing missiles, claiming that such a move would increase his nation's vulnerability to an attack by Warsaw Pact Forces. The treaty text was finally agreed in September 1987. On 8 December 1987, the treaty was officially signed by Reagan and Gorbachev at a summit in Washington and ratified the following May in a 93–5 vote by the United States Senate.