Turkey on Monday urged the United States to reverse a decision to halt the issuing of all regular visas at American consulates in the country, as prosecutors summoned another Istanbul mission staffer in an escalating crisis.
The row, which analysts have described as the worst dispute between the Nato allies in half a century, erupted when Turkey jailed a Turkish employee working at the American consulate in Istanbul.
Ankara hit back at the US move to suspend the issuing of non-immigrant visas with a tit-for-tat response, even sarcastically imitating the language used in the US announcement in its own statement.
The Turkish foreign ministry summoned the US embassy's deputy chief of mission on Monday, urging Washington to reverse its visa decision.
Ministry officials told the diplomat the move was creating "unnecessary escalation and victimisation", state-run Anadolu news agency reported.
The US embassy in Ankara said on Sunday it would suspend issuing visas for tourism, medical treatment, business, temporary work or study, after the arrest last week.
Immigrant visa services are only for those seeking to live in the United States permanently.
Last week an Istanbul court remanded in custody the consulate employee over accusations of links to the group of US-based Muslim preacher Fethullah Gulen who Ankara blames for the 2016 failed coup aimed at unseating President Recep Tayyip Erdogan.
He has been formally charged with espionage and seeking to overthrow the Turkish government, accusations the US embassy rejected as "wholly without merit".
On Monday, Turkish prosecutors summoned another local employee working at the American consulate in Istanbul, the state-run Anadolu news agency said.
Turkish television, including the NTV private channel, said earlier an arrest warrant had been issued for the employee. But this was not confirmed in the Anadolu report.
However, the employee's wife and child, whose age was not given, have been detained in the Anatolian city of Amasya on suspicion of being key members of Gulen's group, it said.
daily reported the individual wanted by prosecutors is currently taking sanctuary inside the Istanbul US consulate.
"It's definitely a historic low in ties, at least in recent memory," said Soner Cagaptay, director of the Turkish Research Program at The Washington Institute, adding that the last such dispute of this magnitude was after the 1974 Turkish invasion of Cyprus.
"Neither side is willing to step back," he said.
'Hard to restore ties'
The developments also came after a Turkish employee at the US consulate in the southern city of Adana was arrested in March on charges of supporting the Kurdistan Workers' Party (PKK).
Turkish officials had expressed hope of a new page in Ankara-Washington relations under President Donald Trump and pressed Washington for the extradition of the Pennsylvania-based Gulen, who denies any link to the coup bid.
The lack of movement on the issue has further strained ties already fraying over Washington's support for a Syrian Kurdish militia Ankara deems to be a terror group.
Meanwhile, members of Erdogan's security detail were indicted by US authorities after clashes with protesters during an official visit this year, infuriating the Turkish president.
American pastor Andrew Brunson, who ran a church in the western city of Izmir, has been held by Turkish authorities since October 2016 on charges of being a member of Gulen's group.
Erdogan suggested last month that Turkey could release him in exchange for Gulen but Washington showed little interest in the proposal.
"It will be hard for relations to be restored any time soon to what they used to be," said Cagaptay.
Turkey's influential Industrialists' and Businessman's Association (TUSIAD) described the move by the US as "most unfortunate", saying it risked hurting citizens who had nothing to do with the row.
The tensions put pressure on the Turkish lira, which lost 3.34% against the US dollar to trade at 3.735 lira while the Borsa Istanbul 100 Index was down 3.02% 100,996 points.
Seeking to reassure markets, the Turkish deputy central bank governor Murat Uysal said: "There could be a temporary impact because of geopolitical concerns, we are watching closely."