AMNA NAWAZ: Welcome to the "NewsHour."

Federal workers were put on notice today that a shutdown is imminent.

Millions of government employees and active-duty military members could stop being paid in just three days' time.

GEOFF BENNETT: The U.S. Senate has been working in a bipartisan manner to prevent a shutdown, but the holdup is with House Republicans, some of whom are refusing to support any short-term measure that would buy Congress more time to act.

Congressional correspondent Lisa Desjardins is on Capitol Hill following all the twists and turns.

Lisa, Congress now has less than three days to reach a deal.

The House and Senate appear to be moving in different directions.

What is the latest this evening?

LISA DESJARDINS: Right.

This deadline is quite serious, and it is approaching more quickly now.

However, things at the Capitol are becoming more complicated, and it feels almost as if slowing down.

First of all, let's talk a little bit about the Senate, which has a compromise idea.

However, a single senator, Rand Paul of Kentucky, is saying he will not allow that to proceed any more quickly than according to Senate rules, because he objects to Ukraine funding in that bill.

Geoff, what that means, essentially, is that we are on track for the Senate to be able to vote on its compromise spending plan no sooner than Monday.

Something would have to change.

So, let's review where we are.

Right now, the shutdown would start for most government agencies Sunday morning at 12:01, just after midnight on Sunday morning here in the country, in America.

And then we know, as I said, that the House, the Senate right now is on track to have a final vote no sooner than Monday.

Now, the House, we don't know what their plan is.

We're waiting to see it.

House Speaker Kevin McCarthy has said he would have one.

He wanted to have a vote on it tomorrow.

But we're waiting to see.

There are so many details up in the air right now, but I think -- think of it in terms of two pivot points, Geoff.

One is tonight.

The House of Representatives will try to pass a yearlong funding bill, possibly two, for a few agencies.

That will be a test if Republicans can agree on anything in the House.

The other pivot point is Saturday.

That's when some senators are going to try and amend that Senate bipartisan deal.

That may be changing.

We will see how many votes there are on Saturday.

We will also see if the deadline itself makes the Senate move a little more quickly.

GEOFF BENNETT: Lisa, you mentioned Ukraine funding.

Remind us of what other issues are at play here.

LISA DESJARDINS: Ukraine funding has been a major factor in both chambers right now.

But we are seeing the rise of Republicans talk more and more about border security.

Initially, the reason we were not able to see spending bills pass in the House and the reason we got to this point was overspending amounts, the idea of the national debt, holdouts saying there had to be lower spending levels than even Republicans themselves agreed to just a few months ago.

That was the real reason we got here, but now we're hearing more and more Republicans say, we also have been concerned about border security.

We want more border security provisions in any kind of temporary deal, and we're hearing that conversation among Senate Republicans as well.

That's what I mean by saying this has become more complicated, not less, as we get toward the shutdown.