Ulaanbaatar (AFP) - A Turkish teacher targeted in a suspected kidnap attempt thwarted by Mongolian authorities Saturday thanked his supporters as he left hospital after a checkup following his ordeal.

When asked who had attempted to abduct him, Veysel Akcay simply said "I don't know."

The drama unfolded Friday as Mongolian authorities grounded a suspected Turkish air force jet after witnesses said assailants snatched a Turkish man associated with a religious group Ankara has branded as terrorists.

In recent weeks, Turkey's intelligence agency has conducted operations abroad against associates of US-based preacher Fethullah Gulen -- who Ankara says was behind a 2016 failed coup against President Recep Tayyip Erdogan.

As many as five men grabbed Akcay from outside his home in Mongolia's capital Ulaanbaatar Friday morning and threw him into a minibus, according to friends and eyewitnesses.

The 50-year-old is director of a school in Mongolia that is alleged to be associated with Gulen, although teachers there denied the connection in response to questions by AFP.

When he failed to show up for work, concerned family and friends notified the police.

Meanwhile, Akcay's abductors had taken him to Genghis Khan international airport, where a small passenger jet landed around 1:00 pm (0500 GMT).

The plane -- with call sign TT4010 -- is operated by the Turkish Airforce, according to data on flight tracking site flightradar24.com.

It was the beginning of a more than eight-hour standoff between the captors and Mongolian authorities, who refused to allow the plane to leave the runway.

As authorities summoned Turkish officials from their embassy in Mongolia, parliamentarians and hundreds of protestors clutching signs demanding Akcay's release gathered at the airport.

As the standoff dragged on, Mongolian vice foreign minister Battsetseg Batmunkh warned Turkish embassy officials that any attempt to abduct a person from Mongolia's territory would constitute "a serious violation of Mongolia's independence and sovereignty".

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Turkish Foreign Minister Mevlut Cavusoglu denied the accusations during a telephone call to his Mongolian counterpart Tsogtbaatar Damdin, according to the Mongolian Ministry of Foreign Affairs.

But officials were not convinced: "We are an independent nation. Do you think anyone can do abductions in our country?" parliamentarian Baasankhuu Oktaybri wrote on Twitter.

The plane took off at 9:25 pm Friday without Akcay, who was taken for questioning by police and later sent to a hospital for medical checks.

"I thank you all," he told his supporters as he left hospital.

- Ankara's relentless hunt -

Sandwiched between China and Russia, Mongolia was once described by former US Secretary of State John Kerry as an "oasis of democracy".

However the incident "might turn into a full diplomatic crisis between Mongolia and Turkey, a relationship that has been active and vibrant for some years," said Julian Dierkes, an expert on Mongolian politics at the University of British Columbia.

The Turkish aid agency "has undertaken many projects in Mongolia, many Mongolian students have studied at Turkish universities", a relationship that could be "damaged," he said.

Since the failed coup in July 2016, Turkey has been relentlessly tracking down those it suspects of being supporters of Gulen, who denies being behind the attempted overthrow of Erdogan.

Gulen's movement built up significant influence in Turkey and overseas, particularly in Central Asia, Africa and the Balkans, especially via its education network.

Ankara has outlawed the movement as a terror organisation but followers insist they promote peace and moderate Islam.

Turkey has carried out a series of overseas operations against suspected members of the movement in places such as Kosovo, Gabon and more recently Ukraine.

Last week a Turkish blogger accused of links to Gulen was deported from Ukraine as part of an operation by MIT while another individual was detained in Azerbaijan recently and sent back to Turkey.

In Turkey more than 77,000 people were arrested over alleged links to the movement during a two-year state of emergency imposed after the coup bid in a crackdown criticised by Ankara's Western allies.