Every nonimmigrant alien who applies for admission to, or an extension of stay in, the United States, shall establish that he or she is admissible to the United States, or that any ground of inadmissibility has been waived under section 212(d)(3) of the Act. Upon application for admission, the alien shall present a valid passport and valid visa unless either or both documents have been waived. However, an alien applying for extension of stay shall present a passport only if requested to do so by the Service. The passport of an alien applying for admission shall be valid for a minimum of six months from the expiration date of the contemplated period of stay, unless otherwise provided in this chapter, and the alien shall agree to abide by the terms and conditions of his or her admission. The passport of an alien applying for extension of stay shall be valid at the time of application for extension, unless otherwise provided in this chapter, and the alien shall agree to maintain the validity of his or her passport and to abide by all the terms and conditions of his extension. The alien shall also agree to depart the United States at the expiration of his or her authorized period of admission or extension, or upon abandonment of his or her authorized nonimmigrant status. At the time a nonimmigrant alien applies for admission or extension of stay he or she shall post a bond on Form I-352 in the sum of not less than $500, to insure the maintenance of his or her nonimmigrant status and departure from the United States, if required to do so by the director, immigration judge or Board of Immigration Appeals.