Election 2024 updates: Trump campaign claims it was hacked by 'foreign sources'

Former President Donald Trump said he "couldn't believe" Vice President Kamala Harris picked Minnesota Gov. Tim Walz as her running mate, adding he "could not be more thrilled," when he called into Fox and Friends Wednesday morning.

"I would say my reaction is, I can't believe it. I never thought this was going to be the one that was picked," Trump said. "He's a very, very liberal man, and he's a shocking pick, and I'm thrilled. I could not be more thrilled."

Asked if his campaign thought Pennsylvania Gov. Josh Shapiro was going to be the VP pick, Trump said he thought Shapiro would've been a better choice.

"I would have said it would have been a better choice," Trump said of Shapiro. "I would have said others were the better, better choice."

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

Vice President Kamala Harris and Minnesota Gov. Tim Walz are scheduled Wednesday to hold rallies in Wisconsin and Michigan, bringing their "vision for the future" to two battleground states on their first full day of campaigning together.

"Together, they will highlight the choice facing Blue Wall voters between the Trump-Vance agenda to weaken unions and give tax cuts to the wealthy on the backs of the middle class, and the Harris-Walz vision for the future, where everyone has the opportunity not just to get by, but to get ahead," the Harris campaign said.

At their midday stop in Wisconsin, the pair will be joined by Gov. Tony Evers and Sen. Tammy Baldwin.

The pair will then travel to Wayne County Airport in Michigan for an evening rally, the campaign said. Gov. Gretchen Whitmer and Detroit Mayor Mike Duggan will join them, the campaign said.

"Their visits come on the heels of over a dozen labor endorsements, including last week's endorsement from UAW -- which represents more than 130,000 members in Michigan alone," the campaign said.

-ABC News' Gabriella Abdul-Hakim, Fritz Farrow and Will McDuffie

Sen. JD Vance will not be making appearances in North Carolina Thursday, due to the forecast of Tropical Storm Debby in the state, the Trump-Vance campaign said in a statement Tuesday.

Vance had two scheduled rallies in Raleigh and Oakboro.

"The Trump-Vance campaign will be rescheduling these events in North Carolina as soon as possible," the campaign said.

Vice President Kamala Harris and Minnesota Gov. Tim Walz's campaign announcement has proven to be a fundraising success, according to a statement from the campaign Tuesday.

The Harris-Walz campaign says it has raised more than $20 million since this morning's announcement of Walz joining Harris on the Democratic ticket in November.