The U.S. Senate Armed Services Committee on Thursday unveiled a draft $750 billion defense policy bill that would authorize more Lockheed Martin F-35 jets for the United States and effectively end Turkey's partnership in the program if Ankara pursues a plan to buy a Russian missile defense system.

In March, U.S. President Donald Trump requested $750 billion for defense, a budget that included more money to build ships and buy jets.

In the coming weeks the U.S. House of Representatives Armed Services Committee, controlled by Democrats, will release its own version of the National Defense Authorization Act (NDAA), which must be reconciled with the version in the Republican-controlled Senate before it can be passed.

Because it sets policy for the Defense Department, the annual NDAA is one of the few bills that Congress passes every year. Because it has become law every year for more than half a century, lawmakers use it as a vehicle for a wide range of policy measures.

This year, the Senate version of the bill would authorize spending on eight F-15X fighter jets as the current aging fleet of about 234 jets is getting more expensive to operate. The defense arm of aircraft maker Boeing Co could potentially make 80 or more of them for the U.S. Air Force.

F-35 The bill authorizes the Pentagon to buy 94 Lockheed Martin-made F-35 stealth fighter jets.

The F-35 comes in three models. The bill authorizes 60 of the F-35A conventional take-off and landing model; 12 of the F-35B, a short take-off/vertical landing version, and 22 of the F-35C, used aboard aircraft carriers.

The F-35 program targets a fleet of more than 3,000 jets, with unit price of the F-35A closer to $80 million in 2020 as more of the aircraft are produced.

Lockheed, the jet's prime contractor, is developing and building the new warplanes for the U.S. military and 10 other countries: Britain, Australia, Italy, Turkey, Norway, the Netherlands, Israel, Japan, South Korea and Belgium.

Strained relations

The NDAA would remove Turkey from the international partnership of nations that have worked together to build the fifth generation F-35 fighter jet.

Like other NATO allies of Washington, Turkey is both a prospective buyer and a partner in production of the F-35. But U.S. officials have said Turkey's plan to buy the Russian system would compromise the security of the F-35 jets.

The dispute has strained relations between Washington and Ankara.

Members of Congress have tried repeatedly to discourage Turkey from buying Russia's S-400 air defense system. An early version of a House appropriations bill released this month also sought to prevent the shipment of F-35 fighter jets to Turkey because of its planned Russian purchase.

Space force

The legislation also authorizes the creation of a Space Force as a separate uniformed service, but still part of the U.S. Air Force.

Islamic State prisoners

Another provision of the bill would create a special U.S. envoy to address the situation of former fighters and supporters of the Islamic State militant group now languishing in detention centers in Syria.