In an action under subsection (a) for an injury arising from an act of international terrorism committed, planned, or authorized by an organization that had been designated as a foreign terrorist organization under section 219 of the Immigration and Nationality Act (
8 U.S.C. 1189), as of the date on which such act of international terrorism was committed, planned, or authorized, liability may be asserted as to any person who aids and abets, by knowingly providing substantial assistance, or who conspires with the person who committed such an act of international terrorism.