India successfully test-fired a surface-to-surface missile developed by its own scientists, Prime Minister Rajiv Gandhi told a cheering Parliament. The United States, the Soviet Union, France and China are the only other countries to have developed such weapons. Gandhi, who received a standing ovation in Parliament when he announced the successful test, said the Prithvi missile was meant to be purely defensive. He said the missile completed a 150-mile flight and plunged into the Bay of Bengal. India detonated an atomic device in 1974 but denies it has any nuclear weapons. Defense experts said the new missile could deliver nuclear warheads but that it would likely be used in conventional roles.