A visas are issued to diplomats and other government officials for travel to the United States. With the exception of a Head of State or Government who qualifies for an A visa regardless of the purpose of his or her visit to the United States, the type of visa required by a diplomat or other government official depends upon their purpose of travel to the United States.
A visa allows a foreign citizen to travel to the United States port-of-entry, and request permission of the U.S. immigration inspector to enter the U.S. A visa does not guarantee entry into the U.S.
Diplomatic applicants must meet specific requirements to qualify for a diplomatic (A) visa under immigration law. The consular officer will determine whether you qualify for the visa.
For an A-1 or A-2 visa, you must be traveling to the United States on behalf of your national government to engage solely in official activities for that government.
The fact that there may be government interest or control in a given organization is not in itself the defining factor in determining if you qualify for an A visa; the particular duties or services that will be performed must be governmental in character or nature, as determined by the United States Department of State, in accordance with U.S. immigration laws. Government officials traveling to the United States to perform non-governmental functions of a commercial nature, or traveling as tourists, require the appropriate visa, and do not qualify for A visas.