In a meeting of the Turkish-US Business Council in New York on Wednesday, Turkish President Recep Tayyip Erdogan pointed fingers at the deterrents in the defense cooperation between Turkey and the US for 'negatively' impacting NATO security, adding: "Artificial obstacles to our defense cooperation with the US, which are contrary to the allied law, also negatively affect NATO security landscape". 

NATO leaders decided Wednesday to formally invite Finland and Sweden to join the alliance after Turkey agreed to withdraw its reservations, according to a statement.

Erdogan further mentioned that due to the pressure mounting from certain lobbies on decision-makers, the partisan approach that emerged eventually harms American interests, as the US earlier submitted an official notice to Turkey regarding its exclusion from the advanced F-35 fighter jet program as a result of Ankara's transaction of Russian S-400 air defense systems. 

The Turkish president's Spokesperson Fahrettin Altun said earlier this year that Washington’s removal of Turkey from the F-35 program in 2019 was "unlawful". The US rejected the delivery of the promised aircraft after Turkey refused its demand to scrap buying S-400s. Altun also shot down an idea raised by Washington that Ankara should transfer its Russian S-400 systems to Ukraine in exchange for the F-35 fighter jets his country had been denied.

After the US rescinded the joint F-35 memorandum with Turkey, seven partners signed in on the F-35 project remained - the UK, Italy, the Netherlands, Australia, Denmark, Canada, and Norway. In light of that, Erdogan continuously stated that the US has attempted to convince Turkey to purchase the fourth-generation fighters, known as the F-16. The US State Department is still lobbying for it while trying to persuade congressmen that it would serve Washington's interest.

In light of that, Robert Menendez, the head of the US Senate Committee on Foreign Relations, told the Greek newspaper Kathimerini that he opposes selling F-16 fighter jets to Turkey unless Ankara changes its political course and fulfills its obligations toward NATO by refusing to purchase Russia's S-400 missile defense system.

Earlier this month, Erdogan said that Turkey may consider countries such as Russia if the US fails to follow through with a pledge to deliver F-16 fighter jets, stating: "The US is not the only one selling warplanes in the world. The UK, France, and Russia sell them as well. It's possible to procure them from other places, and others are sending us signals". 

For the time being, Erdogan reiterated his country's insistence on purchasing more volumes of gas from the US, commenting: "We would like to increase the volume of gas we buy from the US on more favorable terms in the coming period. We are ready to cooperate on the delivery of US liquefied natural gas (LNG) to the countries of the region". 

Turkey receives the majority of its gas supply from Russia, Azerbaijan, and Iran.