House Oversight and Government Reform Committee Chairman Darrell Issa has apologized to Rep. Elijah Cummings, the panel's top Democrat, for turning off his microphone during a testy exchange at the conclusion of a hearing Wednesday.

Cummings said the California Republican telephoned him Thursday evening to say he was sorry for cutting off his microphone and refusing to allow him to speak. The Maryland Democrat said he accepted the apology.

"My sincere hope is that as we move forward, we will respect the opinions of all members of the committee, we will proceed in a deliberate and considered manner to obtain the facts, we will refrain from making accusations that have no basis in fact, and we will seek resolution rather than unnecessary conflict," Cummings said in a prepared statement.

Issa abruptly adjourned the hearing over the IRS' targeting of conservative groups after former agency official Lois Lerner refused to answer his questions.

As Issa gaveled the hearing to a close, Cummings said he had a statement and a procedural question, but the chairman ignored him, saying the hearing was over.

Democrats immediately condemned the action, suggesting that Issa -- who has used the committee to attack the Obama administration since assuming the chairmanship in January 2011-- was trying to muzzle the House's minority party.

All 16 Democratic members of the oversight panel sent Issa a letter Wednesday chastising his actions and asking him to apologize to Cummings. House Minority Leader Nancy Pelosi, D-Calif., also condemned Issa.

Congressional Black Caucus Chairman Marcia Fudge, D-Ohio, on Thursday offered a resolution saying that the House "strongly condemns the offensive and disrespectful manner" in which Issa conducted the hearing. Cummings also is a caucus member. The GOP-run House voted along party lines to table the resolution.

House Speaker John Boehner, R-Ohio, has backed Issa, telling reporters Thursday, "From what I understand, I think Mr. Issa was within his rights to adjourn the hearing when he did."