U.S. and Turkish diplomats continue talks on resolving a dispute over recent visa curbs, as Turkish President Recep Tayyip Erdogan steps up his rhetoric against Washington. Bilateral relations are set to be further strained by an upcoming court case over Iranian sanction busting involving Turkish citizens.

Erdogan launched a scathing attack Sunday on the country’s Western allies.

He warned Turkey would respect its strategic alliances with its partners as long as those countries respected the law. Ankara has accused some of its NATO partners of conspiring against it and offering sanctuary to people it accuses of being involved in last year’s coup.

Erdogan specifically targeted Washington.

“They say the United States is the cradle of democracy. This can not be true, this can not be democracy,” he said. ” If the United States issues arrest warrants for my 13 bodyguards in a country where I went upon invitation, I am sorry, but I will not say that country is civilized.”

Erdogan’s body guards are accused by U.S. prosecutors of assaulting peaceful protesters outside the Turkish embassy during his visit to Washington in May.

The Turkish president’s scathing attack comes as diplomats from both countries are continuing efforts to resolve the mutual curbing of visas.

Washington imposed visa restrictions following the arrest on terrorism charges of two local employees working at U.S. diplomatic missions in Turkey.

That move saw Ankara retaliating with its own visa restrictions.

The U.S. State Department described the talks Thursday as productive.

Political columnist Semih Idiz of Al Monitor website said Erdogan’s increasingly tough rhetoric against Washington should be viewed in a wider context of the importance of bilateral relations to both sides.

“He [Erdogan] is a master of coming out with bellicose remarks at unexpected and sensitive moments. But we must realize Erdogan was in New York very recently and had a very chummy meeting with Donald Trump who called him a special friend. So Turkey is aware for all the problems it has with America, [it] too it has to tread carefully,” said Idiz.

Observers point out Erdogan’s tough rhetoric is in part motivated by domestic politics. A tough anti American stance plays well with Turkish nationalists Erdogan is courting for 2019 presidential and general elections.

But U.S. Turkish relations could be further strained with an upcoming Iranian sanction busting court case in the United States that involves Turkish-Iranian businessmen Reza Zarrab and senior members of a Turkish State bank.

Political consultant Atilla Yesilada of Global Source partners warns the case can only add to bilateral tensions.

“This upcoming Reza Zarrab case which we [Turkey] consider a big conspiracy of the American deep state, so the possibility of these political shocks tampering off is almost nil,” said Yesilada.

Washington’s ongoing support of Syrian Kurdish militia fighting the Islamic State, also continues to infuriate Ankara who accuse the militia of being, linked to an armed insurgency in Turkey.