Hillary Clinton summoned at least three contenders vying to become her running mate to her Washington home on Friday as she closes in on a pick for vice president.

Clinton met separately with Massachusetts Sen. Elizabeth Warren, Colorado Gov. John Hickenlooper and Housing and Urban Development Secretary Julian Castro, according to a person familiar with the process. The person would speak only on condition of anonymity to discuss the private meeting.

Warren and Hickenlooper were seen in separate cars departing the former secretary of state's home Friday afternoon. It was unclear if other potential vice presidential candidates met with Clinton during the day. The meetings came a day after the presumptive Democratic presidential nominee campaigned alongside another potential vice presidential choice, Virginia Sen. Tim Kaine, in northern Virginia.

Clinton's meeting happened the same day Republican presidential candidate Donald Trump named Indiana Gov. Mike Pence to be on the GOP ticket. For Clinton, the Pence selection offered clarity on the composition of the Trump ticket and certainty of whom her eventual running mate will meet in a fall debate.

While the choice of a vice president has rarely had a dramatic impact on the outcome of a presidential race, the decision is among the most consequential for a presidential nominee and offers a window into the candidate's priorities and values.

A small group of Clinton campaign confidants have reviewed publicly available information about the potential contenders for more than a month. The in-person meetings come less than two weeks before Clinton formally accepts her party's nomination at the Democratic National Convention in Philadelphia.

"On Friday, Secretary Clinton held a series of campaign-related meetings at her Washington home, including several about her vice presidential selection process," spokesman Brian Fallon said in a statement. Campaign chair John Podesta and vice chair Huma Abedin were among the Clinton aides who spent the day at her home.

Clinton has been assisted by veteran Democratic lawyer James Hamilton, who has overseen her selection process, along with longtime aide Cheryl Mills, who served as her chief of staff in the State Department.

Kaine, 58, a former mayor and governor from a key general-election battleground state, is considered to be a safe choice for Clinton, someone who could help her appeal to moderates who have been turned off by Trump's divisive rhetoric.

Warren, 67, spent about an hour at Clinton's home, her second visit in the past month. The senator is an economic populist and a favorite of liberals who would help Clinton connect with many of the progressives who backed Vermont Sen. Bernie Sanders during the primaries. Warren would also help form an unprecedented all-female presidential ticket.

Hickenlooper, 64, is a relatively new name in the process and hails from another top battleground state. The second-term governor founded a brewpub in Denver in 1988 and later became the city's mayor and was instrumental in luring the 2008 Democratic National Convention to the Mile High City. He would bring a Western presence to the ticket and offer a small businessman's appeal to a candidate who frequently mentions her father's work as the owner of a small drapery business.

Castro is a 41-year-old former San Antonio mayor who delivered the keynote address at the 2012 Democratic National Convention. He was tapped by President Barack Obama two years later to lead the housing agency. If selected, he would be the first Latino on a presidential ticket.