House Benghazi committee Chairman Trey Gowdy said Wednesday he won’t bow to Democrats' demands in a bitter dispute over access to witnesses and information.

Rep. Elijah Cummings of Maryland, the panel’s top Democrat, has accused Gowdy of operating a “partisan investigation” over the past eight months by holding secret meetings with witnesses and then withholding or downplaying information from those interviews “that undermines allegations the committee is investigating.”

In Wednesday letter to Gowdy, the committee’s five Democrats objected to his plan to go forward with 22 “unilateral and unnecessary” subpoenas to State Department officials without any committee debate or vote.

But Gowdy said that Democrats have refused multiple times to accept a negotiated rules package over demands for veto power over subpoenas. He added he's tried to work out a compromise but that Democrats have refused.

“I am unwilling to let the minority party veto subpoenas when it is clear they have prejudged the outcome of the investigation," Gowdy said. “The minority has repeatedly indicated it is unwilling to issue any subpoenas. If subpoenas are necessary for the committee to talk to relevant witnesses or access relevant documents, they will be issued.”

The Republican-run House voted in May to create a select committee to investigate what led up to the Sept. 11, 2012, attack at a U.S. diplomatic mission in Benghazi, Libya, that killed four Americans.

Democrats generally view the 12-member panel, which includes seven Republicans, as nothing more than GOP grandstanding since several other House committees — most notably the Oversight and Government Reform Committee — already have investigated the attacks.

Gowdy said he will "continue to move the investigation forward in a fair and impartial manner."

"But I will not allow the minority’s political games and unreasonable demands to interfere with the investigation,” he said. “The time for negotiations has passed, and the committee is moving on under the rules and scope approved by Congress.”