Washington — President Biden met with congressional leaders on Wednesday afternoon as a monthslong dispute over border security and aid for Ukraine made its way to the White House.

The high-stakes meeting involving congressional leaders, key committee chairs, ranking members and national security officials focused on supplemental funding for Ukraine, as well as enhanced border security measures and immigration policy changes, lawmakers said after the meeting. 

"I am more optimistic than ever before that we come to an agreement," Senate Majority Leader Chuck Schumer, a New York Democrat, told reporters. 

For months, the supplemental spending package requested by the president has been up in the air after congressional Republicans made their backing contingent on the Ukraine aid being tied to stricter border policies. Senate negotiations aimed at forging a compromise on immigration issues dragged through the holidays and into the new year. 

Seeking to attract a group of moderates from both parties to back the aid package, senators have been circling a middle-ground deal that would represent a major breakthrough after decades of failed efforts in Congress to reform the immigration system.

"There was a large amount of agreement around the table, that we must do Ukraine, and we must do border. There was tremendous focus on Ukraine, and an understanding that if we don't come to Ukraine's aid, that the consequences for America around the globe would be nothing short of devastating," Schumer said.

House Minority Leader Hakeem Jeffries, a New York Democrat, described it as "a very positive, forward-looking, candid discussion" in which there was "broad agreement" that the U.S. should continue to support Ukraine. He said there was also "an openness" to address the situation at the border in a bipartisan manner. 

House Speaker Mike Johnson, a Louisiana Republican, said it was a "productive meeting" and that he was insistent with the president that border security be prioritized ahead of Ukraine aid. 

"We understand that all these things are important, but we must insist that the border be the top priority," Johnson said after the meeting. "I think we have some consensus around that table. Everyone understands the urgency of that." 

Before the meeting, White House press secretary Karine Jean-Pierre said Mr. Biden wanted to lay out why it was urgent to continue supporting Ukraine "and why that's needed now and how that affects our own national security."

Schumer said ahead of the meeting that the upper chamber has "made a lot of good progress" in recent weeks, noting that he's "hopeful that things are headed in the right direction."

But even if the Senate reaches and passes a deal on immigration, its prospects for approval in the House are far from certain.

House Republicans skeptical of Senate immigration talks 

Johnson said at a news conference earlier Wednesday that House Republicans were "anxious" to see the Senate agreement on border security and acknowledged the "thoughtful" negotiations. But he quickly cast doubt on whether there would be support for the immigration reform in the lower chamber.

"I don't think now is the time for comprehensive immigration reform, because we know how complicated that is," Johnson said, noting that it can't be done quickly. "I do think it's past time to secure the border."

House Republicans have stood firm on a demand that a House-passed border security bill known as H.R. 2 be the baseline of any immigration agreement — a nonstarter in the Democratic-controlled Senate. 

Johnson touted H.R. 2 again on Wednesday, noting that it would restore the Trump administration's "Remain in Mexico" policy, end the quick release of migrants into the U.S., reform the asylum and parole processes and resume construction of the southern border wall. 

"Those elements are critically important," Johnson said. "You can't choose from among those on a menu and assume that you're going to solve the problem."

The speaker said House Republicans are "demanding real, transformative policy change," noting that they're "standing on that line," which he said he plans to tell the president at Wednesday's meeting.

He also said House Republicans need answers to "critical questions" about the U.S. strategy in Ukraine and accountability for funding to Kyiv.

"We need to know that Ukraine would not be another Afghanistan," Johnson said. 

When asked how Mr. Biden would navigate Johnson's demand that the border be addressed before Ukraine, Jean-Pierre said the House speaker "is not the only congressperson in the room today." 

"There will be other congressional members," she said. "The president has been really clear. He wants to talk about Ukraine, the urgency of making sure we continue that assistance to Ukraine, what that means not just for the broader world, national security, but also for us." 

Kaia Hubbard

Kaia Hubbard is a politics reporter for CBS News Digital based in Washington, D.C.