President Joe Biden sent to Capitol Hill proposed legislation for his $33 billion assistance package for Ukraine on Friday, but Democrats are divided on how to enact it.

Democratic leaders in Congress and Biden advocate pairing the Ukraine aid with billions in additional money to combat COVID-19 as a way of pressuring Republicans skeptical of the COVID-19 funding to vote for it.

But in a Friday letter to House Speaker Nancy Pelosi and Minority Leader Kevin McCarthy, a group of five representatives, three of them Democrats, said the Democratic leaders’ plan could bog down the flow of aid to Kyiv, which is widely supported in both parties.

In a letter to Pelosi on Thursday, Biden suggested that Congress fold in the Ukraine funds with $22.5 billion in previously requested COVID-19 funding. The pandemic funding, whittled down in talks on Capitol Hill to just $10 billion, has been held up due to a dispute over Biden’s move to end the Trump-era “Title 42” immigration policy barring entry to migrants on public health grounds.

“To avoid needless deaths in the United States and around the world, I urge the Congress to include this much needed, life-saving COVID funding as part of this supplemental funding request,” Biden wrote.

And at her weekly press conference on Friday, Pelosi said she supported pairing the Ukraine aid and COVID-19 funding. “I think it’s very important,” she said. “We have emergencies here. We need to have the COVID money and we need — time is of the essence because we need the Ukraine money.”

But in their letter, Reps. Jared Golden, D-Maine, Jake Ellzey, R-Texas, Jimmy Panetta, D-Calif., Don Bacon, R-Neb., and Kai Kahele, D-Hawaii, said that strategy could backfire. 

“Attaching unrelated COVID-19 legislation — legislation that is currently tied up in a debate about related public health policies — adds uncertainty and precious time to the process of passing this crucial aid. Those debates should happen on their own merits, not with Ukraine’s sovereignty and tens of thousands of innocent Ukrainian lives hanging in the balance,” the lawmakers said. 

And the GOP, so far, appears to feel similarly. 

“We can’t play politics with this. We need to get it done,” Rob Portman, R-Ohio, a co-chair of the Senate Ukraine Caucus, said Thursday.

The letter comes as fighting in Ukraine has shifted to the country’s south and east, across a front line that spans some 300 miles, where the relatively flat terrain has given way to long-range firefights involving artillery and heavy armor. 

Almost half of the supplemental aid package, $16.4 billion, would flow to the Defense Department where it would be used to procure additional weapons and equipment for the Ukrainian military. 

Another $5.4 billion would pay to replenish Defense Department stocks that the White House has already sent to Ukraine, including over 1,400 Stinger anti-aircraft missiles, over 5,500 Javelin anti-armor missiles, 700 Switchblade drones, 90 155mm Howitzers, 200 M113 armored personnel carriers and more than 50 million rounds of ammunition.