((a)) ** .—** In addition to any domestic or extra-territorial jurisdiction otherwise provided by law, the courts of the United States have extra-territorial jurisdiction over any offense (or any attempt or conspiracy to commit an offense) under section 1581, 1583, 1584, 1589, 1590, or 1591 if—
((1)) an alleged offender is a national of the United States or an alien lawfully admitted for permanent residence (as those terms are defined in section 101 of the Immigration and Nationality Act ()); or
((2)) an alleged offender is present in the United States, irrespective of the nationality of the alleged offender.
((b)) ** .—** No prosecution may be commenced against a person under this section if a foreign government, in accordance with jurisdiction recognized by the United States, has prosecuted or is prosecuting such person for the conduct constituting such offense, except upon the approval of the Attorney General or the Deputy Attorney General (or a person acting in either such capacity), which function of approval may not be delegated.