House Democrats Ask Bernie Sanders When He'll Endorse Clinton

Rumbling at a closed-door meeting signaled Democrats' impatience with the delay.

Nearly every member of the caucus -- which gave Clinton a warm welcome in a meeting two weeks ago -– has backed Clinton’s bid.

At one point during the morning meeting, Sanders did not answer pointed questions about when he plans to endorse Clinton -– prompting boos and shouted questions from rank-and-file Democrats.

“Certainly members want to know when he will fully endorse,” said one source in the room. “Nothing I heard was concrete.”

While Clinton promised Democrats she would help them try to take back the House and touted her “50-state” general election plan, Sanders said nothing explicit about his general election role beyond wanting to defeat Trump, according to sources in the room.

Some Democrats were willing to give Sanders -– formerly an independent who caucused with Democrats -– a pass after the contentious primary.

Others in the room, who heard Sanders talk about the need to reform the primary process, were less charitable – and say he now has a responsibility to help Clinton get elected.

“There’s a lot of talk about the party and the caucus and the primaries, but you used the party when it was advantageous for you,” another Democrat said of Sanders.

Sanders did not take questions about the meeting at a news conference following the caucus visit, but told CNN most House Democrats were “really friendly.”

“I don’t know there were a few people who were discontented,” he said of the booing. “But most of the people were really friendly and I think very appreciative.”

ABC’s MaryAlice Parks contributed to this report.