WASHINGTON (Reuters) -President Joe Biden heads to Alabama on Tuesday to visit a Lockheed Martin Co facility that manufactures the anti-tank Javelin missile, putting the spotlight on a weapon that has helped Ukraine fight Russia’s invasion.

Biden will use the visit to press Congress to approve his proposed $33 billion assistance package for Ukraine, including more than $20 billion in military aid, White House press secretary Jen Psaki said Monday.

Biden will “remind people in the country of why we’re fighting, why we’re supporting the Ukrainians in this war, the type of equipment and the type of assistance we are providing from the United States …. and why it is urgent to get this funding across the finish line,” she said.

Aid to Ukraine has not been a subject of the usual partisan bickering among lawmakers. But $20 billion is a huge jump and any legislative proposal can fall victim to political polarization in Washington. Biden, a Democrat, is visiting a state that has backed Republican presidential candidates for decades to avoid that outcome.

The United States has rushed $3.4 billion worth of weapons to Ukraine since Russia invaded on Feb. 24 including howitzers, anti-aircraft Stinger systems, Javelins, ammunition and body armor.

Demand for Javelin missiles remains high as the war shifts from around Kyiv, where they were used to stop Russian tanks from advancing on the capital, to an artillery battle in Ukraine’s east.

So far the United States has sent more then 5,500 Javelin systems to Ukraine, the Pentagon said. According to a Sunday bulletin from Ukrainian officials, 1,026 Russian tanks have been destroyed.

“They’re asking for more obviously,” Jim Taiclet, Lockheed’s chief executive, said of Ukraine’s aims at an Atlantic Council seminar on Friday. The company is trying to expand production capacity at its Troy, Alabama facility and elsewhere, he said.

Raytheon Technologies and Lockheed jointly produce Javelins, while Raytheon makes Stingers.

Lockheed said its Troy facility employs 600, helps manufacture five types of missiles and is the only final assembly plant for the Javelin system, capable of producing 2,100 missiles per year.

Lockheed has been investing to ramp up Javelin production, and may use its own funds to expedite contracts to subcontractors. But supply chain concerns complicate any ramp up. Each Javelin contains about 250 microprocessors, which have been impacted by shortages prompting Congress to weigh legislation that would offer $52 billion in grants for chipmakers to expand operations.

The Pentagon is monitoring the U.S. stockpile of these weapons and their components on a daily basis.

(Reporting by Steve Holland and Mike Stone in Washington; Editing by Heather Timmons, Cynthia Osterman, William Maclean)