A bipartisan group of lawmakers is pressing President Joe Biden directly to send F-16 warplanes to Ukraine as the fight against Russia’s invasion enters its second year.

Five House members argued modern jets — which Kyiv has sought, but the administration has so far not agreed to — “could prove decisive for control of Ukrainian airspace this year” in a Thursday letter to Biden obtained by POLITICO. 

“The provision of such aircraft is necessary to help Ukraine protect its airspace, particularly in light of renewed Russian offensives and considering the expected increase in large-scale combat operations,” the lawmakers wrote.

The letter was organized by Maine Democrat Jared Golden. Also signing on were Democrats Jason Crow of Colorado and Chrissy Houlahan of Pennsylvania and Republicans Tony Gonzales of Texas and Mike Gallagher of Wisconsin.

The missive is the latest push from Capitol Hill to give Kyiv U.S.-made fighters. It also comes as supporters of Ukraine aid in both parties look to navigate a faction in the new House Republican majority that wants to curtail assistance.

The lawmakers contend that fighters — either the Lockheed Martin-manufactured F-16 or something similar — would give Ukrainian forces greater capability than ground-based artillery provided by the U.S. and other nations.

“F-16s or similar fourth generation fighter aircraft would provide Ukraine with a highly mobile platform from which to target Russian air-to-air missiles and drones, to protect Ukrainian ground forces as they engage Russian troops, as well as to engage Russian fighters for contested air superiority,” they argued.

The bipartisan push from Capitol Hill comes after a coordinated U.S.-German decision to send main battle tanks to the front lines. After some wrangling, the U.S. agreed to send Abrams tanks at a future point while Germany will donate Leopard tanks that will enter the field sooner.

But Biden appeared to reject sending F-16s to Ukraine last month, though the president later said he’d speak to Ukrainian President Volodymyr Zelenskyy.

Even if Biden elected not to send U.S. F-16s, other Western nations that fly the American-made fighters could send them to Ukraine, though the U.S. would need to approve the transfer.

POLITICO reported the move has picked up steam at the Pentagon. But some argue there’s a greater need for artillery, air defenses and armor for Ukraine.

U.S.-made F-16s have been on Kyiv’s wish list for weapons since Russia’s invasion began a year ago. Lawmakers have also said the U.S. should send F-16s to Eastern European that transfer their old MiG fighters to Ukraine. That move won bipartisan support, though a weapons swap never came.

In their pitch to Biden, the lawmakers argued a decision on F-16s “must be made quickly” given the time needed to train Ukrainian pilots.

Still, they noted many Ukrainian pilots have already trained with the U.S. military in major exercises before the war and argued sending the jets “represents a sound strategic investment in bolstering Kiev’s military capability and bringing this conflict to a just conclusion.”