Leasing an airbase in Peshawar in 1950s, the Central Intelligence Agency's spy activities grew immensely during his presidency but such activities were exposed in 1960 when the Soviet Union's air defence intercept and shot down the U-2 plane by the S-75 missile, and captured its pilot. This incident severely compromised the national security of Pakistan that brought the Soviet ire on Pakistan but President Ayub had all knowledge of the operation and full aware of what happened in the Soviet Union. While in United Kingdom to pay state visit, the CIA station chief told President Ayub who shrugged his shoulders and said that he had expected this would happen at some point.