Turkey urged the United States yesterday to review its suspension of visa services after the arrest of a US consulate employee sharply escalated tensions between the two Nato allies and drove Turkey's currency and stocks lower.

Relations between Ankara and Washington have long been plagued by disputes over US support for Kurdish fighters in Syria, Turkey's calls for the extradition of a US-based cleric and the indictment of a Turkish former minister in a US court.

But last week's arrest of a Turkish employee of the US consulate in Istanbul marked a fresh low. Turkey said the

employee had links to US-based Muslim cleric Fethullah Gulen, blamed by Ankara for a failed military coup in July 2016.

The US embassy in Ankara condemned those charges as baseless and announced on Sunday night it was halting all nonimmigrant visa services in Turkey while it reassessed Turkey's commitment to the security of its missions and staff. Within hours Turkey announced it was taking the same measures against US citizens.

Yesterday, the Turkish foreign ministry summoned a US diplomat to urge the United States to lift the visa suspension, saying it was causing "unnecessary tensions”.

Justice Minister Abdulhamit Gul said that if Washington had serious security concerns about its missions in Turkey, steps would be taken to address them.

"But if it's an issue regarding the arrest of the consulate employee, then this is a decision the Turkish judiciary has made," Gul told A Haber television. "Trying a Turkish citizen for a crime committed in Turkey is our

Turkish media reported that authorities had issued a detention warrant for a second US consulate worker. Reuters could not immediately confirm the reports, which also said the employee's wife and child were being questioned by police.

The diplomatic spat spooked investors. The lira dropped 2.4 percent and stood at 3.7030 against the dollar after being quoted