 Iran massed over 300,000 troops on the Afghan-Iranian border and threatened to invade Afghanistan to depose the Taliban, a government which it had never recognized.This strained Iran's relations with Pakistan, which continued to support the Taliban government.In May 1998, Pakistan conducted its first ever nuclear weapons tests (codenamed "Chagai-I"), detonating five nuclear weapons at a controlled facility in its Balochistan province in response to Indian tests (codenamed "Pokhran-II") a few days earlier, both events would later lead to U.N. sanctions on both Pakistan and India, but did not stop either country from continuing to conduct more tests.