Since August 1996, the Iran-Libya Sanctions Act (ILSA) has imposed mandatory and discretionary sanctions on non-U.S. companies that invest more than $20 million annually (lowered in August 1997 from $40 million) in the Iranian Oil and Natural Gas sectors. On August 3, 2001, President Bush signed into law the ILSA Extension Act of 2001. This provided for a 5-year extension of ILSA with amendments that affect certain of the investment provisions. In addition, the United States has maintained various sanctions against Iran since 1979, following the seizure of the U.S. embassy in Tehran on November 4 of that year. In 1995, President Clinton signed two Executive Orders prohibiting U.S. companies and their foreign subsidiaries from conducting business with Iran. Executive Order 12957 specifically banned any "contract for the financing of the development of Petroleum resources located in Iran." On March 10, 2005, President Bush extended sanctions for another year, citing Irans "continued support for terrorism, its efforts to undermine the Middle East peace process and its efforts to acquire weapons of mass destruction."