The Secretary of State shall, subject to the availability of appropriations, pay all necessary travel and other expenses of persons described in subsection (a)(1) of this section and of not more than six experts and advisers authorized under section
5601
(e) of this title with respect to their actual performance of their official duties pursuant to this chapter, in accordance with the Federal Travel Regulations and sections
5701,
5702,
5704 through
5708, and
5731 of title
5.