The US mission in Turkey and subsequently the Turkish mission in Washington mutually scaled back visa services after a US consulate employee was arrested in Turkey, in the latest sign of fraying diplomatic relations between the NATO allies.Last week, the US mission employee in Istanbul was arrested on charges of links to a cleric blamed for last year's failed coup, a move condemned by Washington as baseless. "Recent events have forced the United States government to reassess the commitment of government of Turkey to the security of US mission and personnel," the mission in Ankara said in a statement."In order to minimize the number of visitors to our embassy and consulates while this assessment proceeds, effective immediately we have suspended all non-immigrant visa services at all US diplomatic facilities in Turkey."The Turkish embassy in Washington followed suit, and made virtually the same statement, only replacing the country names.The state-run Anadolu news agency identified the consulate employee as a male Turkish citizen and said he was arrested late on Wednesday on charges of espionage and attempts to damage the constitutional order and Turkey's government.Turkey has expressed deep frustration over its so far fruitless calls for the United States to extradite Fethullah Gulen over a failed July 2016 coup, in which more than 240 people were killed. Gulen denies any involvement.Thousands of people have been detained in a crackdown since the failed coup, including American Christian missionary Andrew Brunson, who ran a small church in Izmir on Turkey's western coast. The United States has said that Brunson has been wrongfully imprisoned and has called for him to be released.Diplomatic relations between Turkey and the United States have particularly deteriorated since May, when Turkish security officials were involved in street fighting with protesters during a visit to Washington and were subsequently indicted.In September, Turkey also protested the US indictment of a former Turkish economy minister for conspiring to violate US Iran sanctions, saying the charges amounted to a "coup attempt" through American courts.Turkey is a member of the North Atlantic Treaty Organization and is part of the US-led coalition against Islamic State in Syria and Iraq. But Ankara's ties with Washington are strained over support provided by the United States to the Syrian Kurdish militia YPG.Viewed by Turkey as the Syrian extension of the outlawed Kurdistan Workers Party (PKK), the YPG has been among the most effective partners on the ground in the US-led fight against the Islamic State.