In the aftermath of the invasion, Carter was determined to respond vigorously to what he considered a dangerous provocation. In a televised speech, he announced sanctions on the U.S.S.R., promised renewed aid to Pakistan, and committed the U.S. to the Persian Gulf's defense. Carter also called for a boycott of the 1980 Summer Olympics in Moscow, which raised a bitter controversy. British prime minister Margaret Thatcher enthusiastically backed Carter's tough stance, although British intelligence believed "the CIA was being too alarmist about the Soviet threat to Pakistan." The thrust of U.S. policy for the duration of the war was determined by Carter in early 1980: Carter initiated a program to arm the mujahideen through Pakistan's ISI and secured a pledge from Saudi Arabia to match U.S. funding for this purpose. U.S. support for the mujahideen accelerated under Carter's successor, Ronald Reagan, at a final cost to U.S. taxpayers of some $3 billion (per Riedel, based on congressional appropriations). The Soviets were unable to quell the insurgency and withdrew from Afghanistan in 1989, precipitating the dissolution of the Soviet Union itself. Of the seven mujahideen groups supported by Zia's government, four espoused Islamic fundamentalist beliefs—and these fundamentalists received most of the funding.