Updated

Six months before American-born Muslim cleric Anwar al-Awlaki was killed by an American drone strike in Yemen, he was invited to the U.S. Embassy in Sana’a – in order for the embassy to revoke his passport -- according to newly released State Department documents.

The documents, obtained by Judicial Watch and reviewed by Fox News, show that the embassy was instructed to send a message to al-Awlaki requesting that he pick up an “important letter” in person at the embassy in March 2011.

This letter, which embassy employees were instructed not disclose to al-Awlaki before his appearance at the embassy, was the revocation of al-Awlaki’s passport, based on a determination by the State Department that his “activities abroad are causing and/or likely to cause serious damage to the national security or the foreign policy of the United States.”

There's no evidence available that he ever collected the letter.

A former Diplomatic Security agent who worked for the State Department in the Middle East told Fox News the revocation of the passport was “highly unusual.” The agent, who asked to remain unnamed, added, “there may be a legal finding by the Justice Department that allowed State Department officials to take this extraordinary step.”

Al-Awlaki was killed in September 2011 in Yemen by a CIA-led U.S. drone strike. Pulling the passport would have had two effects – it would box al-Awlaki in, limiting his travel, and it would allow the administration to argue the CIA drone campaign targeted a foreign national, not an American citizen. Al-Awlaki was a dual Yemen-U.S. national.

Judicial Watch obtained the documents from the State Department through a Freedom of Information Act result first submitted in September 2011, right after the strike.

Documents turned over in compliance with a related records request also reveal the State Department noting the death of al-Awlaki’s 16-year-old son, also born in the United States. The son was killed in a U.S. drone strike two weeks after his father.

Though the circumstances of the death are well documented, the State Department took the routine step of producing a “Report of Death of American Citizen Abroad,” in which the cause of death was listed as “unknown.”