(AFP) -- Erdogan said Turkey no longer regarded ambassador John Bass as the US representative to Turkey after American missions in the country stopped issuing visas.
The dispute erupted last week when Turkey arrested a Turkish employee of the American consulate on suspicion of links to the group blamed for last year's failed coup.
In response, the United States stopped issuing non-immigrant visas from its missions in Turkey, prompting Turkish missions in the United States to hit back with a tit-for-tat step of their own.
"We have not agreed and are not agreeing to this ambassador making farewell visits with ministers, the parliament speaker and myself," Erdogan said at a news conference with President Aleksandar Vucic in Belgrade.
"We do not see him as the representative of the United States in Turkey."
Bass is shortly to leave Turkey after being nominated the US envoy to Afghanistan and it is traditional for outgoing envoys in Turkey to make valedictory visits to top officials.
Although Bass is in Turkey for only a few more days, it is unprecedented in the history of Turkish-US relations for Ankara to say it no longer recognises Washington's ambassador.
- 'Agents in consulate' -
Erdogan said the arrest of the consulate staffer, based on evidence found by the police, shows "something is going on at the Istanbul consulate."
Some Turkish officials have long alleged a US hand in the coup attempt on July 15 last year, which Ankara blames on the US-based Muslim preacher Fethullah Gulen.
Washington has dismissed claims it was involved as a ludicrous conspiracy theory and Gulen himself denies any link to the plot.
"The US should evaluate one thing: how did those agents leak into the consulate?" Erdogan said.
The US embassy has dismissed the allegations against the arrested consulate staffer as baseless.
On Monday, Turkish prosecutors summoned another local employee working at the American consulate in Istanbul, the Anadolu news agency said.
The man is reportedly in hiding at the consulate but the Turkish authorities on Monday detained his wife and his son, and on Tuesday detained his daughter.
In March, a Turkish employee at the US consulate in the southern city of Adana was arrested on charges of supporting the Kurdistan Workers' Party (PKK).
"The current crisis is unlikely to be de-escalated with ease," said Anthony Skinner of Verisk Maplecroft, a risk consultancy.
(Photo: AFP)