 Privately, Bush ignored Baker's assurances and later pushed for NATO expansion.On the trip, the U.S. informed Gorbachev of its evidence that the Soviet military—possibly unbeknownst to Gorbachev—had been pursuing a biological weapons program in contravention of the 1987 Biological Weapons Convention.In July, Kohl visited Moscow and Gorbachev informed him that the Soviets would not oppose a reunified Germany being part of NATO.