WASHINGTON – Congressional Democrats and Republicans are preparing a massive, multi-billion-dollar aid package for Ukraine, hoping to address a fast-worsening humanitarian crisis and bolster the region’s defenses against any further Russian incursion.

In a Capitol often wracked by partisanship, the two parties have found early common ground this week in calling for prompt passage of an emergency spending measure, which some lawmakers believe will ultimately exceed the Biden administration’s initial request to deliver roughly $6 billion in foreign assistance.

“I’ve heard some senators talking about as much as $10 billion,” said Sen. Tim Kaine, D-Va., a top lawmaker on the chamber’s Armed Services Committee, adding he “suspect[s] we will act in a very vigorous way.”

Many of the details remain unresolved, and early schisms emerged Tuesday, as Democrats and Republicans quibbled over the exact amounts that would be set aside for humanitarian aid or defense and how they will be provisioned. GOP lawmakers in particular would like to see far more money appropriated for defense, especially military assistance to Ukraine.

With the clock ticking, though, Democratic leaders Tuesday pressed lawmakers to move more swiftly. In the Senate, Majority Leader Charles Schumer, D-N.Y., called on Democrats and Republicans to act on a “bipartisan basis, and in lockstep with the Biden administration, to pass a strong aid package.”

“The strongest signal we can send to [Russian President] Vladimir Putin right now is the United States stands together, together, with the people of Ukraine,” Schumer said in a speech to open the chamber floor.

Top Democrats said they hope to attach any new aid to a must-pass bill that would fund the government beyond March 11, when the current spending agreement is set to expire. Absent congressional action next week, key federal agencies and operations stand to shutter, potentially testing Washington as it tries to manage an ever-evolving list of domestic and international challenges.

For now, the long-term funding deal remains unfinished. But Democrats and Republicans have stressed in recent days that they are making significant, encouraging progress – and believe the recent tumult in Ukraine might provide an added political jolt for a Congress that’s at times slow to act.

“Let me put it this way: I’m hoping this emergency [aid] will spur more action on the omnibus,” said Sen. Chris Van Hollen, D-Md., a top lawmaker on the spending-focused Senate Appropriations Committee.

“The process needs to move more quickly,” he said. “We’ve got some ways to go to finish it up. The need to pass emergency funds to support Ukraine will help drive that process.”

The flurry of work on Capitol Hill comes days after the Biden administration urged lawmakers to approve $6.4 billion in emergency assistance for the war-torn country. The request called for about $2.9 billion for the State Department and other agencies, which would be tasked with providing humanitarian and security assistance to Ukraine as well as other states in the region, including Poland and Lithuania. And it proposed another $3.5 billion to boost efforts at the Defense Department, according to White House officials, who described their request last week on the condition of anonymity given the sensitive, early nature of the talks.

In sketching out their request, the Biden administration stressed the situation remains fluid and the spending needs could change, especially as Russia continues to encroach on Kyiv and other major Ukrainian cities. And they called on Congress to attach the aid to their still-forming, longer-term spending deal, which could fund the government through the end of the fiscal year

“The administration will continue to closely coordinate with our European allies and partners to assess on-the-ground needs, and remain in close touch with Congress as these needs evolve,” an official said at the time.

On Tuesday, party lawmakers signaled optimism they can meet the fast-approaching deadline: House Majority Leader Steny Hoyer, D-Md., told his colleagues the House intends to vote on the broader package March 8, three days before the current spending stopgap runs out. Other policy proposals could come before Congress later in March, aides anticipate.

But a “snag” emerged later in the day, in the words of Senate Minority Leader Mitch McConnell, R-Ky., who spoke to reporters after his party’s weekly lunch. The potential flash point stemmed from the way in which Democrats had hoped to provision some of the funds for Ukraine. While the proposed humanitarian aid would be new, coming in addition to sums already set aside for the rest of the fiscal year, the defense-related spending would be redirected from part of the Pentagon’s proposed budget, according to the GOP leader.

“We’re not going to do that. This is an emergency,” McConnell said.

Asked about the discrepancy, Sen. Patrick J. Leahy, Vt., the top Democrat on the Appropriations Committee, pledged only that any aid set aside for Ukraine would be substantial. And he signaled an unwillingness to negotiate at length on the specifics of the proposal.

“I’m not going to go back and forth, and back and forth, and back and forth. We’re going to have aid to Ukraine,” he said.

The emergency aid also could complement a suite of additional congressional efforts to boost Ukraine and penalize Russia. That includes a renewed push among Democrats and Republicans to punish the Kremlin and its allies, for example, with a focus on sanctions on its energy sector or a slew of oligarchs who may have escaped the measures levied recently by the United States and Europe.

Other lawmakers have floated a desire to target cryptocurrency, seeking to ensure Russian elite don’t traffic in the hard-to-track digital money to evade sanctions affecting Russian banks. And still another group of House Democrats have floated a proposal to end normal trade relations with Russia, an idea that drew early interest from both parties’ lawmakers in the Senate on Tuesday.

“I’m intrigued by that,” said Sen. Mike Crapo, R-Idaho., the top Republican on the Senate Finance Committee. “I haven’t decided whether to push that yet, but it’s something I’m very interested in.”

Sen. Mark Warner, D-Va., the leader of the chamber’s intelligence committee, said Tuesday he’s seeking to couple humanitarian and defense aid with a proposal that would help battle back potential Russian cyberattacks on U.S. businesses and other entities. His measure would require businesses to disclose major digital intrusions, part of a range of issues that arose when the Ukrainian ambassador briefed Warner and other lawmakers during a private meeting late Monday.

“The concern I have is there’s real-time need,” Warner said, adding there “may be more” in aid adopted by Congress than the White House initially sought.

Some Republicans, however, signaled this week they may prefer to handle the matters separately. Sen. Richard Shelby, R-Ala., the top GOP lawmakers on the Senate Appropriations Committee, told reporters Monday that federal funding and Ukraine aid “ought to be separate” – though he said the procedural quibbles mattered little “as long as they move” through Congress.

In advancing Ukraine aid, Democratic leaders said they further hope to approve billions of dollars to bolster the U.S. response to the coronavirus pandemic, replenishing key federal funds for tests, therapeutics and vaccines. The Biden administration previously had asked for more than $35 billion in coronavirus aid across a slew of federal agencies, including about $5 billion to deliver inoculations globally.

Some Democrats hope to ratchet up spending even further, including a push to provide $7 billion toward a global vaccination effort, according to a person familiar with the matter who requested anonymity to describe the private, fluid negotiations. But some of the party’s ideas have faced early Republican resistance. GOP lawmakers in recent weeks have said the Biden administration should seek to repurpose existing, unspent stimulus money before asking Congress to approve more, since lawmakers already have given the green light to roughly $6 trillion in pandemic aid since the crisis began.

Lawmakers from both parties also have pushed in recent weeks for still another tranche of spending to boost performance spaces, restaurants and other small businesses still suffering financially. But that push – at one point valued nearly $70 billion – has failed to attract sufficient support among Republicans, according to Van Hollen, a Democrat who supported the effort.

– – –

The Washington Post’s Marianna Sotomayor and Seung Min Kim contributed to this report.