Communists under the leadership of Nur Muhammad Taraki seized power in Afghanistan on April 27, 1978. Following an uprising in April 1979, Taraki was removed by Khalq rival Hafizullah Amin in September. By December, Amin's government had lost control of much of the country, causing the Soviet Union to invade Afghanistan. Carter was surprised by the invasion. In the West, the Soviet invasion of Afghanistan was seen as a threat to global security. In the aftermath of the invasion, Carter saw the Soviet Union as dangerous. In a televised speech, he announced sanctions on the Soviet Union. He created an embargo on grain shipments to the Soviet Union. Carter also called for a boycott of the 1980 Summer Olympics in Moscow. British prime minister Margaret Thatcher supported Carter's tough stance. In early 1980, Carter created a program to arm the mujahideen. The Soviets were unable to fight off the insurgency and withdrew from Afghanistan in 1989.