U.S. lawmakers are determined to approve more financial aid and weapons for Ukraine’s defense against Russia, two top Democrats said Sunday.

Sen. Tim Kaine (D., Va.) said that work will start on Monday and that it already has widespread support in Congress. The bill is so important because it is essential not just to Ukraine, but to preserving global security, Sen. Robert Menendez (D., N.J.), chairman of the Senate Foreign Relations Committee, said in an interview with NBC News.

“We shouldn’t wait around,” Mr. Kaine said on CBS’s “Face the Nation.” “My colleagues in Congress on both sides, with very few exceptions, they understand how significant this is. There’s quite a bit of bipartisan resolve on a Ukraine aid package.”

The U.S. and its allies are now shipping large volumes of heavy weaponry to Ukraine, including more advanced Western systems to supplement the light weapons and Soviet-era arms that were funneled into Ukraine since before the invasion started.

Those shipments are aimed at supporting Kyiv in the next decisive phase of the war in coming weeks—but also to arm the country in a conflict that could last for months or longer.

Outrage over alleged Russian atrocities has recently spurred calls for more aggressive aid. President Biden has more than doubled the size of the latest funding request to Congress. On Thursday, he asked for $33 billion to fund more weapons and provide longer-term assistance to Kyiv, after an initial $13.6 billion in funding for Ukraine to help cover the first two months of the war was nearly depleted.

Rep. Michael McCaul (R., Texas) said on ABC’s “This Week” that the aid could help the Ukrainians go on the offensive and push Russian forces out of Ukraine’s eastern provinces, which could be decisive.

If Ukraine ultimately succeeds, then “others who are looking at what is happening in Ukraine will have to think twice,” Sen. Menendez said. He called Russian president Vladimir Putin “the butcher of Moscow” and said the “ability not to have to send our sons and daughters into battle is priceless.”

“I think we will do what it takes to see Ukraine win because it’s not just about Ukraine. It is about the international order,” he added.