In an embarrassment for Washington, a high-ranking Turkish military officer on a posting to a Nato base in Virginia claimed asylum in the United States.

Turkish admiral Mustafa Ugurlu had been on a posting to a Nato base in Virginia at the time of the 15 July botched coup and had recently been recalled home by the Turkish government.

The rear admiral had been working at Nato’s Allied Command Transformation headquarters in Norfolk, Virginia, where 26 Turkish military are posted. Mustafa Ugurlu had gone missing and has failed to report back home following a failed coup by renegade officers within the Turkish military. He had left his ID and badges at his base on July 22 and has not been heard from since.

In April he took part in a Nato conference in Poland and was identified as the Western military alliance’s Assistant Chief of Staff for Command and Control, Deployability and Sustainability based in Norfolk.

The issue could complicate US-Turkish ties. Ankara is already pressing Washington to extradite U.S.-based Muslim cleric Fethullah Gulen, who it accuses of orchestrating the coup. Gulen denies involvement.

The asylum bid is the first known case involving a Turkish military officer in the United States as Turkey purges military ranks after mutinous soldiers commandeered fighter jets, helicopters and tanks in an unsuccessful attempt to oust President Tayyip Erdogan.

The purges within Turkey’s military, which has NATO’s second largest armed forces and aspires to membership in the European Union, has resulted in thousands of soldiers being discharged, including around 40 percent of generals.

There are concerns within the Turkish opposition that the restructuring lacks parliamentary oversight and is going too far.

The Norfolk mission where the Turkish officer was assigned is the only NATO command in North America, according to its website. It directs Allied Command Transformation’s subordinate commands, including the Joint Warfare Center in Norway and the Joint Force Training Center in Poland.

The case comes as Turkey presses Washington to hand over U.S.-based cleric Fethullah Gulen.

Gulen, an ally of Erdogan in the early years after his Islamist-rooted AK Party took power in 2002, has denied any involvement in the coup, which came at a critical time for a NATO state facing Islamist militant attacks from across the border in Syria and an insurgency by Kurdish rebels.

Some 18,000 people have been placed in detention in response to the failed coup, including many from the military. The government said on Monday that more than 200 soldiers suspected of involvement in the coup, including nine generals, were still at large.

Many more have lost their jobs or been suspended across Turkey’s public services, on suspicion of being Gulen followers.