Republican presidential candidate Donald Trump speaks at a campaign rally in Spokane, Wash., on May 7, 2016. (Reuters/Jake Parrish)

A top emissary for presumptive Republican presidential nominee Donald Trump has asked to meet privately with House Speaker Paul D. Ryan (R-Wis.) this week in advance of Trump’s visit to Washington on Thursday, according to three people familiar with the matter.

Ben Carson, the retired neurosurgeon who has become one of Trump’s most trusted allies, reached out Monday to Ryan’s political advisers to request a private session with the speaker, according to the sources, who spoke on the condition of anonymity because of the sensitivity of the matter.

The outreach by Carson is an apparent effort both to soothe tensions between Trump and Ryan ahead of their highly anticipated meeting on Capitol Hill and to establish a framework for that discussion.

When reached Monday by phone, Carson’s business manager, Armstrong Williams, said Carson “is a guy who can bring people together.”

“Donald Trump trusts him and the speaker trusts him,” Williams said. “He wants to do the will of the people.”

Ryan’s office declined to comment Monday, but an aide to the speaker confirmed that Carson did request a meeting. The aide said that a meeting has not yet been set but Ryan is hopeful to meet or talk with Carson.

House Speaker Paul Ryan says he cannot support Donald Trump. Trump says he doesn't care. Can the two work out their differences? (Deirdra O'Regan/The Washington Post)

The discussions come as Trump moved Monday to soften his tone about the speaker, following several days of heated exchanges that began when Ryan told CNN last week that he was not yet ready to endorse Trump.

On Thursday, Trump is also scheduled to meet with Senate Majority Leader Mitch McConnell (R-Ky.), Republican National Committee Chairman Reince Priebus and members of the Senate and House leadership as part of his overtures to GOP establishment figures in Washington, many of whom are wary of his candidacy.

In conversations with Trump in recent days, Carson offered his assistance in brokering a peace with Ryan, telling Trump that he has had a warm rapport with the House speaker in the past and could be helpful. Trump then gave Carson his blessing to reach out to Ryan, according to one of the sources.

For Trump, a billionaire real-estate mogul, dispatching an ally to coordinate topics or terms in advance of a formal meeting is a common negotiating tactic.