By Jeremy Diamond, Jim Acosta and Sara Murray CNN

(CNN) -- Donald Trump's campaign is scrambling to ramp up its planning for the general election, including scraping together a list of potential vice presidential candidates, after Trump abruptly became the presumptive Republican nominee Tuesday night.

The Trump campaign, blindsided by rival Ted Cruz's sudden exit from the race, is now beginning internal deliberations about potential vice presidential candidates, two Trump campaign sources tell CNN.

The campaign will also begin coordinating immediately with the Republican National Committee to calibrate a general election ground game, including staff hires and deciding in which battleground states to deploy field staff, a senior Trump adviser said.

Trump campaign manager Corey Lewandowski told reporters Tuesday night before election results in Indiana drove Cruz out of the race that the campaign had yet to start vetting vice presidential candidates.

Trump confirmed Wednesday that his campaign is beginning to put together a committee to weigh in on his pick for running mate. The committee will include former presidential rival and now-Trump supporter Ben Carson, the former neurosurgeon's adviser Armstrong Williams confirmed to CNN.

A senior Trump campaign source said Wednesday that the campaign's early favorites for vice president are now New Mexico Gov. Susana Martinez, South Carolina Gov. Nikki Haley and Sen. Rob Portman of Ohio.

A spokesman for Portman said the senator, who is in the midst of an intense Senate reelection campaign, is "not interested."

"He's focused on his own race," said Kevin Smith, his spokesman.

CNN has reached out to Martinez and Haley's offices for comment.

The source stressed that the shortlist is in its infancy.

Haley, who endorsed Sen. Marco Rubio against Trump in her state's primary, has been highly critical of Trump and warned voters against flocking to "the siren call of the angriest voices" -- a thinly veiled dig at Trump.

Martinez has also not shied away from criticizing the brash New York billionaire and Portman has refused to say whether he would support Trump as the nominee.

Trump, in an interview with CNN on Wednesday, said that he would also like to vet Ohio Gov. John Kasich, who is expected to drop out of the presidential race Wednesday afternoon, as a potential running mate.

Trump has repeatedly stressed that he would pick a running mate with political and government experience -- versus a businessman like himself -- whose relationships with powerful members of Congress could help him pass his agenda legislatively.

CNN's Nia-Malika Henderson, Dana Bash and Tal Kopan contributed to this report.

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