; and (2) prohibit any United States person from engaging in any transaction with a person described in paragraph (1). 7. Imposition ofCAATSA section 231 sanctions against Turkey (a) Determination For the purposes of section 231 of the Countering America’s Adversaries Through Sanctions Act ( 22 U.S.C. 9525 ), Turkey’s acquisition of the Russian S–400 air and missile defense system beginning July 12, 2019, shall be considered to be a significant transaction described in such section. (b) Sanctions Not later than 30 days after the date of the enactment of this Act, the President shall impose 5 or more of the sanctions described in section 235 of the Countering America’s Adversaries Through Sanctions Act ( 22 U.S.C. 9529 ) with respect to the Government of Turkey. 8. Prohibition on United States military assistance (a) Prohibition No funds may be obligated or expended to sell or transfer any United States defense articles, services, technology, or materials or ammunition to the Turkish Armed Forces. (b) No use of emergency authorities The authority of the President to waive statutory congressional review periods under the Arms Export Control Act ( 22 U.S.C. 2751 et seq.) in cases in which an emergency exists shall not apply to the transfer of defense articles or services to Turkey. 9. Prohibition on purchases of Turkish sovereign debt by United States persons The President shall prescribe regulations prohibiting any United States person from purchasing sovereign debt of the Government of Turkey. 10. Visa restrictions on certain officials of the Government of Turkey (a) In general The Secretary of State may not issue a visa to, and the Secretary of Homeland Security shall exclude from the United States, an official of the Government of Turkey described in section 4(b). (b) Exception to comply with international obligations Subsection (a) shall not apply to the admission of an official described in section 4(b) if the admission of that official is necessary to comply with United States obligations under the Agreement