US officials are pressuring Turkey to prohibit Russian airlines from flying US-made airliners from and into Turkey, the Wall Street Journal reported on Thursday, citing officials familiar with the matter.

Senior Biden administration officials warned in December that Turkish individuals could face prison sentences, fines, and loss of export privileges, among other sanctions, if they were found to be providing US-made aircraft flying to and from Russia and Belarus with services such as refueling and spare parts, stressing that it would be in violation of export controls imposed in 2022.

Following the start of the war in Ukraine, various states closed off their airspace to Moscow.

Russia's Federal Agency for Air Transport said the restrictions affected flights from and to 36 countries and ended the supply of aircraft, parts, and services to Russia, and the country has some 515 airliners leased from other states.

According to the officials, Assistant Secretary of Commerce Thea Rozman Kendler handed over the message to Turkish officials during a December visit to the country.

The WSJ reported that the US warning Ankara came as a test for the United States' allies and whether they would be able to isolate Russia over the long run or whether the latter would be able to circumvent the West's sanctions through developing countries.

Continued Russian flights have raised safety concerns, as Washington had banned the sale of critical spare parts to Russia, WSJ said.

In October 2022, US officials, in talks with their Turkish counterparts, addressed compliance with financial sanctions imposed on Russia regarding the war in Ukraine - this comes as the latest move from the West to pressure Turkey into taking a tougher stance towards Russia. 

Elizabeth Rosenberg, the assistant secretary for terrorist financing and financial crimes at the US Treasury, led a delegation to meet the Turkish governor of the central bank, along with business groups in both Istanbul and Ankara earlier this week. 

This visit came a week after Turkish President Recep Tayyip Erdogan and Russian President Vladimir Putin held discussions in Astana, Kazakhstan. The meeting led the two leaders to agree to boost energy ties and to set up an international gas hub in Turkey, allowing Turkey to become a key route for Russian energy flows into Europe, particularly after the West blew up Nord Streams 1 and 2. 

Turkey, after the war, has been deepening its economic and trade ties with Russia, prompting Western worries. In June, Deputy US Treasury Secretary Wally Adeyemo visited Turkey to warn Ankara against doing business with Russia. 

The US Treasury in September issued a warning against Turkey if they were to go through with the Russian Mir payment system. This, at the time, alarmed Turkey: The 5 Turkish banks that were participating in the payment system quit it. 

Meanwhile, Turkey not joining the West's sanctions against Russia has raised concerns in the European Union with EU foreign policy chief Josep Borrell expressing his concerns over the deepening of economic relations between Moscow and Ankara, stating it is "a growing cause for concern."

Borrel said both countries had signed a customs agreement to ensure the free movement of dual-purpose goods, that is, goods that can be used for civil and military purposes, further warning "it was important that Turkey did not offer Russia any solution to the sanctions."

Since the start of the Ukraine war, Ankara has never approved of Western-imposed sanctions of Russia, going as far as critiquing the West's approach in undermining the strength of Russia. 

Turkish President Recep Tayyip Erdogan said the West, with particular emphasis on the US, was "attacking Russia almost without restrictions."

"Russia is not an ordinary state, it is a powerful state. Of course, the West, led by the US, attacks Russia almost without restrictions. In the face of all this, Russia, of course, is resisting. We are also trying to figure out how we can open a corridor for peace from here... We believe that the best way to do this could be from dialogue to peace," Erdogan underlined.