WASHINGTON (AP) — Final congressional approval of a $40 billion Ukraine aid bill seems certain within days as top Senate Republicans said Wednesday they expect strong GOP backing for the House-passed measure, signaling a bipartisan, heightened U.S. commitment to helping thwart the bloody Russian invasion.

"I think there'll be substantial support," Senate Minority Leader Mitch McConnell, R-Ky., told The Associated Press about the legislation, which cleared the House late Tuesday by an emphatic 368-57 margin. "We're going to try to process it as soon as possible."

No. 2 Senate GOP leader John Thune of South Dakota predicted "a big vote over here" for the bill, which he and others suggested might come Thursday but could spill into next week. Thune said some Republicans would vote against it and procedural tactics by opponents to slow it were possible, but added, "I think because there's so much forward momentum behind doing this and doing it in a timely way that it I don't think we'll have anybody who will hold it up."

It's taken just two weeks for lawmakers to receive President Joe Biden's smaller, $33 billion package, enlarge it and move it to the brink of passage — lightning speed for Congress. That reflects a bipartisan consensus that Ukraine's outnumbered forces need additional Western help as soon as possible, with added political pressure fueled by near-daily tales of atrocities against civilians inflicted by Russian President Vladimir Putin's armies.

"Act quickly we must," said Senate Majority Leader Chuck Schumer, D-N.Y. "I will make sure this is a priority for the Senate. We have a moral obligation to stand with our friends in Ukraine."

The new legislation would bring American support for the effort to nearly $54 billion, including the $13.6 billion Congress enacted in March. That's about $6 billion more than the U.S. spent on all its foreign and military aid in 2019, according to a January report by the nonpartisan Congressional Research Service, which studies issues for lawmakers.

Washington has become increasingly assertive about its goals and its willingness to help Ukraine with more sophisticated weapons. Defense Secretary Lloyd Austin said recently the U.S. wants a "weakened" Russia that can't quickly restore its capability to attack other countries, and reports have emerged about U.S. intelligence helping Ukrainians kill Russian generals and sink the Russian missile cruiser Moskva.

A senior Russian official said in Moscow Wednesday that the assistance package was part of Washington's proxy war against Russia. Dmitry Medvedev, deputy head of Russia's Security Council and former president, said on a messaging app that the aid was driven by a desire to "inflict a heavy defeat on our country, restrict its economic development and political influence in the world."

The measure sailed to House passage backed by every voting Democrat, while around 1-in-4 Republicans opposed it. It would provide $7 billion more than Biden's request from April, dividing the increase evenly between defense and humanitarian programs.

The bill would give Ukraine military and economic assistance, help regional allies, replenish weapons the Pentagon has shipped overseas and provide $5 billion to address global food shortages caused by the war's crippling of Ukraine's normally robust production of many crops.

"As Putin desperately accelerates his campaign of horror and brutality in Ukraine, time is of the essence," said House Speaker Nancy Pelosi, D-Calif.

Some Republicans used the election-season debate to accuse Biden of being unclear about his goals.

"Honestly, do we not deserve a plan?" said Rep. Michael Burgess, R-Texas. He said he agrees that Western countries must help Ukraine stand up to Russia but added, "Does the administration not need to come to us with where we are going with this?"

Oksana Markarova, Ukraine's ambassador to the U.S., attended Tuesday's separate Democratic and Republican Senate lunches and expressed gratitude for the support they've received. Sen. Chris Coons, D-Del., said Markarova told them her country has depleted its stockpiles of Soviet-era weapons and said continued NATO support is vital.

Coons said the Ukrainian's message was: "Thank you, do more. We have a hard fight ahead. With your support, we can win."

The new measure includes $6 billion to arm and train Ukrainian forces, $8.7 billion to restore American stores of weapons shipped to Ukraine and $3.9 billion for U.S. forces deployed to the area.

There's also $8.8 billion in economic support for Ukraine, $4 billion to help Ukraine and allies finance arms and equipment purchases and $900 million for housing, education and other help for Ukrainian refugees in the U.S.

To enhance the measure's chances in Congress, the House bill dropped Biden's proposal to ease the pathway to legal permanent residency for qualifying Afghans who fled to the U.S. after last summer's American withdrawal from that country. Some Republicans have expressed concerns about the adequacy of security screenings for applicants.

In their biggest concession, Biden and Democrats abandoned plans Monday to include additional billions of dollars to build up U.S. supplies of medicines, vaccines and tests for COVID-19. Republican support for more pandemic spending is waning and including that money would have slowed the Ukraine measure in the 50-50 Senate, where at least 10 GOP votes will be needed for passage.

Democrats hope to produce a separate COVID-19 package soon, though its fate is unclear.