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 Soviet Union, promised renewed aid to Pakistan, initiated renewed registration for the Selective Service System, and committed the U.S. to the Persian Gulf's defense. He imposed an embargo on grain shipments to the USSR, tabled consideration of SALT II, and requested a 5% annual increase in defense spending. Carter also called for a boycott of the 1980 Summer Olympics in Moscow. 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. The Soviets were unable to quell the insurgency and withdrew from Afghanistan in 1989, precipitating the dissolution of the Soviet Union itself. However, the decision to route U.S. aid through Pakistan led to massive fraud, as weapons sent to Karachi were frequently sold on the local market rather than delivered to the Afghan rebels; Karachi soon "became one of the most violent cities in the world." Pakistan also controlled which rebels received assistance: Of the seven mujahideen groups supported by Zia's government, four espoused Islamic fundamentalist beliefs—and these fundamentalists received most of the funding. Despite this, Carter has expressed no regrets over his decision to support what he still considers the "freedom fighters" in Afghanistan.