Earlier, a source told Sputnik's sister agency that Warsaw has been closely monitoring the F-35 spat between Washington and Ankara, hoping to jump the queue if Turkey is dropped out of the program.

The United States is preparing the terms for Poland's order of F-35s, a senior Trump administration official has told reporters.

"They [Poland] have already submitted a letter of request for the F-35, and we're working through our formal military sales process right now to get them an offer eventually," the official said at a press briefing.

The official denied that President Trump and Polish President Andrzej Duda would announce a major arms contract including the F-35 aircraft during Duda's six-day trip around the United States, which starts Wednesday, saying he was not aware of any such decision at this time.

Earlier, a source said that Polish authorities were closely monitoring the conflict between the US and Turkey over Anakara's purchase of Russia's S-400 air defence systems, which Washington has repeatedly warned may result in non-delivery of Turkey's F-35s.

"Poland…is in the queue for these plans, and even if the United States wants to sell these planes to Poland, under normal conditions, Warsaw did not have a chance to get them before Turkey. And now Turkey will simply be removed from the queue," the source said.

Late last month, Polish Defence Minister Mariusz Blaszczak said he hoped to accelerate talks with the US side on the sale of F-35s to Poland. Earlier this year, the Polish military rolled out a $48.5 billion framework to modernise the country's armed forces up to the year 2026, envisioning replacing Poland's stocks of Soviet-era Su-22 and MiG-29 fighters with 32 Lockheed Martin F-35s. The planes normally have an estimated price tag of between $94 million and $122 million apiece.

On Tuesday, the Turkish foreign ministry blasted a resolution by the US House of Representatives promising to withhold F-35 deliveries to Turkey and to slap Ankara with sanctions if it does not back out of its commitment to buy Russia's S-400s. Turkey has been a partner nation in the F-35 development effort since the program's inception, and provides several components to the planes. Ankara sought to buy up to 120 jets over the next few decades. The Pentagon has given Ankara until the end of July to drop out of its S-400 deal, saying it won't get if its F-35s if it fails to do so.