Until 1990, the United States provided military aid to Pakistan to modernize its conventional defensive capability. The United States allocated about 40% of its assistance package to non-reimbursable credits for military purchases, the third-largest program behind Israel and Egypt. The remainder of the aid program was devoted to economic assistance. Sanctions put in place in 1990 denied Pakistan further military assistance due to the discovery of its program to develop nuclear weapons. Sanctions were tightened following Pakistan's nuclear tests in response to India's May 1998 tests and the military coup of 1999. Pakistan has remained a non-signatory of the Nuclear non-Proliferation Treaty. The events of September 11, 2001, and Pakistan's agreement to support the United States led to a waiving of the sanctions, and military assistance resumed to provide spare parts and equipment to enhance Pakistan's capacity to police its western border and address its legitimate security concerns. In 2003, President Bush announced that the United States would provide Pakistan with $3 billion in economic and military aid over 5 years. This assistance package commenced during FY 2005.