The United States Citizenship and Immigration Services (USCIS) requires employers based in the U.S. to verify the identity and work permissions of each employee that they hire. The I-9 Employment Eligibility Verification Form is the employer's documentation that he has fulfilled this legal requirement. Instead of filing the form, employers are required to keep it on file for a period of three years from the date of hire or for one year after the employment is terminated, whichever is later. Employers must keep this form accessible and surrender it for inspection upon the request of authorized government officials, including agents working with the Department of Homeland Security, the Department of Labor, or the Office of Special Counsel. Employees must provide proof of both their identities and their employment authorization. For example, a U.S. Passport is considered proof of both identity and authorization to work, because it establishes that an individual is a U.S. citizen. A driver's license on the other hand, does not establish immigration status or citizenship; therefore, in addition to a driver's license or other State-issued identification card, an employee would be prompted to provide a document such as a birth certificate, social security card or Native American tribal document in order to prove that he has the right to work in the United States.