Harris' vetting team met with Pennsylvania Gov. Josh Shapiro and Arizona Sen. Mark Kelly -- two vice presidential hopefuls, according to sources familiar. The vetting team has met with other candidates as well, the sources added.

As meetings continue, the pool of vice presidential candidates has narrowed from a dozen, sources said.

Harris only has days to make a decision on her running mate. This process that normally takes months has been truncated and her team is doing it in weeks.

Harris is set to begin a tour of battleground states with her running mate on Tuesday.

-ABC News' Selina Wang, Will McDuffie and Katherine Faulders

Vice presidential candidate Sen. JD Vance visited the U.S.-Mexico border in Arizona Thursday morning. During his visit, Vance addressed the press, blaming Vice President Kamala Harris for what he claimed was a failure of the southern border.

"They started their administration, Kamala Harris came into office making promises, and she kept those promises, to open the American southern border," Vance said. "They stopped deportations on Day 1, they stopped construction of the border wall on Day 1, we see the border wall sitting here ready to be completed behind us, and that can't happen because of Kamala Harris' administration."

Vance has said that in a Trump-Vance administration, he would want to be influential in border policy. The border and immigration are a major issue for voters this election.

Vance and Trump have sought to attack Harris over her handling of the border -- something President Joe Biden assigned her to oversee as vice president.

Vance often connects the border to the issue of drug trafficking and the fentanyl crisis, and he did it during his remarks Thursday.

"And the unfortunate truth is, because of the poison that Kamala Harris has let come into this country, there are a lot of those prayers that won't be answered," Vance said. "There are a lot of parents that won't wake up because when you take fentanyl, you don't wake up, it takes your life."

But that is not true. The majority of fentanyl smuggled into the U.S. is through ports of entry, not through migrants.

Vance said the U.S. must implement "common sense policies" at the border.

"You've got to reimplement remain in Mexico. You've got to stop catch and release. You've got to force the asylum seekers to stay in Mexico while their claims are being adjudicated. And you've got to finish this border wall and reimplement deportations," he said.

-ABC News' Hannah Demissie

Republican vice presidential nominee JD Vance said he feels former President Donald Trump has confidence in him, according to an interview he did with NOTUS conducted on Wednesday and published Thursday.

"I think that any Republican who comes out of the gate as the new VP nominee is gonna get attacked. I have no doubt that the president is confident in the way that I've been doing things," Vance said in the interview.

Vance said he and Trump have a "good relationship" and that it will keep on going through all the way to November, hopefully past that too."

In the interview, Vance also said "there was a fallout in the aftermath of the November 2020 election."

Vance said, "I think it's weird to engage in hypotheticals given the law's changed here" when asked how he would have handled a situation where Trump wanted him to act against the Constitution, as then-Vice President Mike Pence said he was asked to during the process of certifying the 2020 election.

This goes against what Vance said in an interview with "This Week" anchor George Stephanopolous in February. During that interview, Vance was willing to discuss what he would have done in 2020 -- before some laws changed​.

"If I had been vice president, I would have told the states, like Pennsylvania, Georgia and so many others, that we needed to have multiple slates of electors and I think the U.S. Congress should have fought over it from there," Vance said then. "That is the legitimate way to deal with an election that a lot of folks, including me, think had a lot of problems in 2020. I think that's what we should have done."

-ABC News' Hannah Demissie and Oren Oppenheim

In a social media post Thursday morning, former President Donald Trump shared a family portrait of Vice President Kamala Harris.

"Your warmth, friendship, and love of your Indian Heritage are very much appreciated," Trump wrote as the caption.

His social media post doubles down on his false claim that Harris only emphasized her Asian-American heritage, something he mentioned during his interview at the National Association of Black Journalists convention on Wednesday.

During the interview, he falsely questioned Harris' race. Harris is the daughter of a Jamaican father and an Indian mother.

"I didn't know she was Black until a number of years ago when she happened to turn Black and now, she wants to be known as Black. So, I don't know, is she Indian or is she Black?" Trump said during the NABJ interview.

He went on to say that "she was Indian all the way, and then all of a sudden she made a turn, and she went -- she became a Black person."

-ABC News' Lalee Ibssa, Soorin Kim and Kelsey Walsh