(a) Services performed by an employee in the employ of certain instrumentalities of a foreign government are excepted from employment. The exception includes all services performed in the employ of an instrumentality of the government of a foreign country, if—

(1) The instrumentality is wholly owned by the foreign government;

(2) The services are of a character similar to those performed in foreign countries by employees of the United States Government or of an instrumentality thereof; and

(3) The Secretary of State certifies to the Secretary of the Treasury that the foreign government, with respect to whose instrumentality exemption is claimed, grants an equivalent exemption with respect to services performed in the foreign country by employees of the United States Government and of instrumentalities thereof.

(b) For purposes of this exception, the citizenship or residence of the employee is immaterial.