Story highlights Donald Trump will meet Wednesday with Henry Kissinger

The former secretary of state has expressed reservations about Trump's candidacy

(CNN) Donald Trump will sit down with former Secretary of State Henry Kissinger Wednesday, two sources close to the campaign told CNN.

This is one of several meetings the presumptive GOP nominee has held with Republican establishment leaders and figureheads in recent weeks, as he aims to unite the party around him before November. The face-to-face was first reported in the Washington Post.

Sources declined to offer details on the meeting.

In December, when asked about Trump's ban on Muslims, Kissinger told Fox Business Network that he didn't "favor an exclusion on the basis of religion ... if he were the Republican nominee he would urge him not to make such a blanket exclusion." Kissinger then added that he would be more comfortable with another nominee.

Last week while in Washington, D.C., Trump met with former Secretary of State James Baker.

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