WASHINGTON — The U.S. State Department on Friday pre-emptively approved a sale of F-35s to Belgium, opening the door to an expedited purchase once the country selects its future fighter.

The proposed deal, worth an estimated $6.53 billion, would cover 34 F-35A conventional takeoff and landing models made by Lockheed Martin and 38 F-135 engines manufactured by Pratt & Whitney.

It also includes electronic warfare systems, communications gear, a full mission trainer and Lockheed’s Autonomic Logistics Information System — which facilitates maintenance, mission planning and logistics — as well as other equipment, the Defense Security Agency stated.

While it’s uncommon for the State Department to green-light a weapons sale ahead of a final decision by a foreign nation, it’s not unheard of, particularly for high-profile deals with close allies. Most recently, the department ok’ed a sale of 18 Boeing F/A-18E/F Super Hornets to Canada this September, but a final agreement never materialized due to a trade dispute.

The F-35 is overwhelmingly considered the favorite for the Belgian fighter competition, which will replace the country’s 54 F-16s with 34 new jets. Should Belgium select the joint strike fighter, the total value of the deal will likely change after negotiations, as DSCA often puts forward a high contract estimate.

Competing against the joint strike fighter are the Dassault Rafale — which the French government is aggressively promoting — and the Eurofighter Typhoon, which is manufactured by a consortium of BAE Systems, Leonardo and Airbus.

The field had been much more crowded at the start of 2017, with Boeing vying to sell more Super Hornets and Swedish aerospace manufacturer Saab putting forward the Gripen E.

Sweden pulls out of Belgian fighter battle Sweden will not put forward Saab’s Gripen E for Belgium’s fighter contest, the country’s defense ministry announced Monday.

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However, Boeing withdrew from the contest in April, saying that it could not fairly compete in a matchup skewed toward the F-35.

Then in July, the Swedish government crushed Saab’s chances, with Sweden its decision to abstain from the competition due to the fact that the government could not meet Belgium’s operational support requirements.

After Saab dropped out, Byron Callan, director of the Capital Alpha Partners investment consulting firm, predicted the F-35 would win.