ANKARA - The US move to suspend visa services in Turkey was motivated both by Washington's concern over Ankara's Syria policy, and by last week's arrest of an embassy employee who allegedly had information on American involvement in the 2016 failed coup attempt, a senior Turkish official told to Al Jazeera.
The US mission in Turkey announced on Sunday that it had stopped all non-immigrant visa services amid concerns over "the security of US mission and personnel". Ankara reiterated reciprocally hours later, using similar language.
The development is unprecedented between the two NATO allies and represents a major fallout in bilateral relations.
Turkish authorities last week detained Metin Topuz, a Turkish citizen working for the US consulate in Istanbul. He was accused of having links to the organisation of Fethullah Gulen, an exiled religious leader and businessman based in the US and wanted in Turkey. Ankara accuses Gulen of masterminding the July 15 coup attempt that killed more than 300 people.
Turkish President, Recep Tayyip Erdogan has repeatedly called on Washington to extradite Gulen since the coup attempt, but the US has refused.
Another US consulate employee was called for questioning by the Istanbul prosecutor's office on Monday as his son and wife were taken into custody in Amasya province. Turkish authorities say that both Metin Topuz and the second unnamed employee have no diplomatic immunity or title.
Turkey summoned the US embassy undersecretary on Monday and called for the de-escalation of tensions and an end to the suspension of visa services.
Several US citizens were among the thousands detained in Turkey after the coup attempt, including American pastor Andrew Brunson. President Donald Trump unsuccessfully appealed to Turkey for his release, along with a letter signed by 78 members of Congress.
Erdogan said last month that Ankara would release the pastor once Gulen was extradited to Turkey.
The Turkish government says that the recent wave of detentions and purges in the public sector are aimed at removing Gulen supporters from state institutions and other parts of society.
Local and international rights groups, as well as many of Turkey's European allies, say the arrests and purges are arbitrary, accusing the government of using the coup attempt as a pretext to silence opposition in the country.
Burhan Kuzu, an adviser to Erdogan and a senior MP of the ruling Justice and Development Party, told Al Jazeera that the US was disturbed by the detention of Topuz, as he had information about US involvement in the coup attempt.
"The US was irritated by this development as its (Washington's) role in the coup attempt might be revealed through this individual. The visa move came in order to pressure Turkey to give up this person," he said.
Al Jazeera was not able to reach US authorities for a response to these claims. October 9 is a public holiday in the US.
On Friday, John Bass, the outgoing ambassador to Turkey, said at a press briefing that the arrest and related reports on Turkish media did not strike him "as pursuing justice" but "more a pursuit of vengeance".