WASHINGTON -- Presumptive Democratic presidential nominee Hillary Clinton sat down with Elizabeth Warren Friday morning in Washington, a meeting coming just hours after Warren endorsed Clinton.

Little was revealed about the content of their conversation. A source familiar with the meeting said Clinton and Warren discussed how they can work together during the campaign and push a progressive agenda aimed at stopping presumptive Republican nominee Donald Trump. And Clinton also thanked Warren for her endorsement, according to a Clinton campaign official.

The two women have never been seen as particularly close, and the face to face discussion is an indicator that Clinton is serious about putting Warren on a vice presidential short list. It’s also a nod to supporters of rival Vermont Senator Bernie Sanders, many who wanted Warren to run for president.