Donald Trump is on the verge of picking his vice presidential running mate.
Top contenders have been told to expect a decision as early as Thursday afternoon.
On Mr Trump's shortlist are believed to be Indiana governor Mike Pence, New Jersey governor Chris Christie and former House speaker Newt Gingrich.
Mr Pence quickly exited a speaking event in Indianapolis on Thursday morning without taking questions from reporters. His staff have not released details of any other planned appearances on Thursday.
All three of the finalists have had extensive conversations with Mr Trump and his family in recent days.
Mr Gingrich said he was expecting to hear from Mr Trump one way or the other some time after 1pm. The former Georgia congressman praised Mr Trump for running a "very fair, open process" and said he looked forward to learning of the businessman's decision.
Mr Trump and his new running mate will make their first appearance as a team on Friday in New York. The timing is aimed at energising Republicans ahead of next week's Republican convention in Cleveland.
Each of Mr Trump's contenders would add significant political experience to the ticket. Mr Trump, a political novice, has said for weeks that he wanted a running mate who could help him work with Congress.
Beyond their political backgrounds, the finalists bring different strengths to the ticket.
Mr Pence, 57, is a steady, staunch conservative who would help calm nervous Republicans wary of Mr Trump's impulsive style. He served six terms in Congress before becoming Indiana governor.
He also has deep ties to evangelical Christians and other conservatives, particularly after signing a law last year that critics said would have allowed businesses to deny service to gay people for religious reasons.
Mr Trump took notice of Mr Pence during the Indiana primary, noting that the governor had high praise for him despite endorsing one of his rivals.
Mr Gingrich is a boisterous rabble-rouser who has spent decades in Washington and helped define the political battles of the 1990s. The 73-year-old would be the oldest candidate ever to become vice president.
Mr Gingrich has been a steadfast Trump defender for months and has become a trusted adviser to the businessman.
Mr Christie quickly endorsed Trump after ending his own presidential bid, stunning many of his supporters.
The former US attorney, aged 53, is widely seen as one of the party's most talented politicians. He has also become a valuable partner for Mr Trump, joining him at events on the trail and taking on the important role of heading his transition planning.