WASHINGTON — Lawyers for a former Republican staffer fired from the House Benghazi committee on Tuesday challenged comments by the panel’s GOP chairman, calling them “unequivocally false” in an escalating internal dispute just days before Democratic presidential candidate Hillary Rodham Clinton testifies.

The former staffer, Air Force Reserve Maj. Bradley Podliska, has said he raised concerns about a partisan investigation focused on Clinton, who was secretary of state at the time of the Sept. 11, 2012, attacks. The panel’s chairman, South Carolina Rep. Trey Gowdy, said he was unaware of Podliska’s concerns.

But on Tuesday, lawyers Peter Romer-Friedman and Joe Napiltonia said top staff members on the panel were fully aware of the concerns raised by Podliska before firing him in late June.

The charges and countercharges among Republicans emerged ahead of Clinton’s scheduled appearance before the Benghazi panel on Oct. 22 and amid fierce partisan fighting about the true nature of the investigation. Clinton and other Democrats call it a partisan political exercise designed to “exploit” the deaths of four Americans and hurt her bid for the White House.

Gowdy and other Republicans say the committee has been and remains focused on those killed in Benghazi and on providing a definitive account of the attacks. There have been at least seven previous investigations.