President Recep Tayyip Erdogan said Friday that Turkey may turn to countries such as Russia if the US fails to follow through a pledge to deliver F-16 fighter jets.

Turkey was kicked out of a programme to replace a wide range of fighter, strike and ground attack aircraft for NATO allies after it acquired an advanced Russian missile defence system in 2019.

But with US-Turkish relations warming in response to Russia's invasion of Ukraine, US President Joe Biden told Erdogan in June that he would support the sale of less advanced F-16 jets.

This has failed to gain traction in Congress, whose support of military sales is required, because of concern among leading US lawmakers about Turkey's tough rhetoric against its traditional foe Greece.

"The US is not the only one selling war planes in the world. The UK, France and Russia sell them as well," Erdogan told reporters after Friday prayers.

"It's possible to procure them from other places, and others are sending us signals," Erdogan said.

Erdogan has made a string of positive comments about Russia ahead of a scheduled meeting with President Vladimir Putin at a regional summit in Uzbekistan next week.

He accused the West of staging "provocations" against Russia by supplying Ukraine with weapons and blamed European sanctions for the continent's energy crisis.

Erdogan also revealed that he had asked Putin to offer Turkey a discount for the natural gas it imports from Russia.

Ankara's strategic ties with Washington have been strained for years by issues ranging from Turkey's deteriorating human rights record to US cooperation with a Kurdish militia in Syria Erdogan views as "terrorists".

Erdogan said he will raise US military support for the Kurdish militia if he has a chance to meet Biden on the margins of an annual UN General Assembly meeting starting on September 13.