AILSA CHANG, HOST:

Well, it's looking like control of the U.S. Senate is going to come down to three very close races in three states. Georgia's Senate race will go to a runoff next month. And so for now, all eyes are on Arizona and Nevada, where the results are still being counted. We've got reporters out in the southwest - NPR's Deepa Shivaram in Las Vegas, Nev., and NPR's Ximena Bustillo in Phoenix, Ariz. Hey to both of you.

XIMENA BUSTILLO, BYLINE: Hey.

DEEPA SHIVARAM, BYLINE: Hey.

CHANG: So, Deepa, I want to start with you 'cause I understand Clark County's Election Department has wrapped up their daily press conference. What are we learning at this point?

SHIVARAM: Yeah. So the registrar of voters here in Clark County, which encompasses Las Vegas - his name is Joe Gloria. And he's holding these daily press conferences that have been happening every day since Election Day to brief reporters, take questions. And what we've learned is that there are still about 50,000 ballots in Clark County that need to be counted. Gloria said that he thinks a majority of those ballots will be counted by Saturday. So that's the day we're all keeping an eye on. It's not going to be a holiday weekend for these election workers, and they're going to keep working through the weekend and into next week. And there are still ballots that are going to be counted after Monday as well. So it's not just ending on Saturday. That's not exactly the end all, be all. Those are going to be some of the ballots that have to be cured, which means that the signatures on them didn't match up. And that's getting checked through the end of the business day on Monday.

Plus, there's about 5,000 provisional ballots that were cast in person on Election Day. Those have to get certified and gone through the secretary of state's office here, and they'll be counted mid-week next week. And, of course, all of this impacts these really tight races in Nevada. The one we're all watching, of course, is the Senate race with incumbent Democratic Senator Catherine Cortez Masto. Her Republican challenger is Adam Laxalt. But we're waiting for results on the governor's race as well and a few of these competitive House races, too.

CHANG: OK, so a lot unresolved still. Ximena, Maricopa County in Arizona is in a similar situation, right? Like, what are election officials telling you right now?

BUSTILLO: Yeah, absolutely. So in this county, you have three ways to vote - mail-in, drop-off and in-person. According to election officials, state law requires all mail-in and dropped off ballots to be individually signature-verified. And then those ballots have to go through a bipartisan processing board, which is a team of two people that check the ballot. And then it goes into tabulation and is counted. This year the county experienced a record number of these ballots. On Election Day itself, over 290,000 voters dropped off a ballot at a polling location on Election Day as opposed to voting in person or mailing it in the day before or any time before. That's 100,000 more than last election, which held the record until this year.

So it's important to remember that each state has different laws and rules, and the day of drop-offs are specific to Arizona. The calls day after the election are also not new for the state. For example, when Sinema won in 2018, you know, a different Senate seat in the state of Arizona, that was not called by the Associated Press until about a week after Election Day. The key question is the partisan split of the votes being tabulated today in Maricopa, and how close they are running together is similar, as Deepa just said, for Nevada. That will determine if the Associated Press will be able to call the race for the Senate and the governor, which are the tightest right now as well.

CHANG: Right. OK. Well, Deepa, former President Trump has weighed in here, posting on his platform Truth Social, saying without any evidence that Clark County has a corrupt voting system. I'm curious. How have election officials responded to Trump?

SHIVARAM: Yeah. This is something we were all kind of waiting and watching to see - not only what the former president would say but also, you know, a lot of these election deniers that are running in Nevada - Secretary of State Adam Laxalt here in the Senate race - in Arizona as well and all over the country - how they're going to weigh in here as this process goes on and as we go, you know, into next week, more than a week after Election Day.

And election officials here in Nevada were quick to respond to Trump. They said that what Trump said on his platform, again, without any evidence is outrageous and that he's misinformed about the law and the process here in Nevada, which, by the way - by the law, it's designed to take this long. It's not out of the blue that we don't have some of these ballots counted. And Gloria, the registrar of voters that I talked about earlier - he said there are concerns about security with Trump's comments, especially for these election workers - there's hundreds of them here in Clark County alone - when Trump says these things. Here's what he said earlier today.

(SOUNDBITE OF ARCHIVED RECORDING)

JOE GLORIA: Unfortunate comments like the one that came out today from former President Trump get certain people very fired up, and they're convinced that we are doing things that are inappropriate or against the law. And that's just not the case.

CHANG: All right. That is NPR's Deepa Shivaram in Las Vegas and Ximena Bustillo in Phoenix. Thanks to both of you. Transcript provided by NPR, Copyright NPR.