Sanctions under subsection (a)(8) shall not apply to an alien if admitting the alien into the United States is necessary to permit the United States to comply with the Agreement regarding the Headquarters of the United Nations, signed at Lake Success June 26, 1947, and entered into force November 21, 1947, between the United Nations and the United States, the Convention on Consular Relations, done at Vienna April 24, 1963, and entered into force March 19, 1967, or other applicable international obligations.