Sen. Bernie Sanders (I-Vt.) received a tough reception from House Democrats on Wednesday morning, with many encouraging him to endorse Hillary Clinton and some showering him with boos when he declined to do so.

Coming a day after the FBI announced that it would not bring charges against Clinton for her use of a private email account while at the State Department, Sanders' meeting with the House Democratic caucus illustrated the fraying patience that a faction of the Democratic Party has for his still-going campaign. Several sources in the room confirmed the boos, with one member saying that lawmakers "were visibly annoyed that he was making this about him and not about winning an election for the American people."

A high-ranking aide called it a "lousy presentation" that was filled with "platitudes and no specifics," though Rep. Gerry Connolly (D-Va.) tried to downplay the tension in subsequent tweets.