WASHINGTON — The FBI agent who worked on separate investigations of Donald Trump's campaign and Hillary Clinton's use of private email said that he is sorry he sent inflammatory tests about Trump, according to two Democratic sources who heard last week's closed-door House testimony by the agent.

Agent Peter Strzok had exchanged anti-Trump texts with FBI lawyer Lisa Page. Both worked on the Clinton investigation and also on the Special Counsel Robert Mueller's probe of possible collusion between the Trump campaign and Russia.

The sources said that during the joint closed-door session held by the House Judiciary and Oversight committees on June 27, Strzok apologized for the texts and regretted having sent them. They said Strzok told the joint session that his work was driven by the evidence and not bias.

They said he also said he was part of a large team and could not have steered any investigation out of bias even if he wanted to.

According to the sources, Strzok was prohibited by FBI lawyers from answering many of the substantive questions asked by members of the committees. They also said Republican members expressed interest in having Strzok back for a public hearing.

Strzok faces internal discipline from the FBI. He was escorted from FBI headquarters on June 19.

Stzrok's lawyer did not respond to a request for comment. A Republican with knowledge of the session did not immediately respond to a request for comment.