"Either people have gotten tired of Benghazi or they never knew about it in the first place," the California Democrat told reporters Friday at the Capitol. "It's all subterfuge because they don't want to talk about what our responsibilities are here" in Congress.
The GOP-run House on Thursday rammed through a measure to establish a 12-member select committee to probe the attacks. The panel was set up to include seven Republicans and five Democrats, though Pelosi says that -- for now -- Democrats won't participate.
"Let's not be accomplices to this diversionary tactic," she said.
Pelosi added that the Republicans' push for a new Benghazi panel was the result of GOP Rep. Darrell Issa's failure to lead his own probe of the attacks.
Five House committees have been investigating the attacks, most notably the Oversight and Government Reform Committee led by Issa, R-Calif.
But Pelosi said Republican leaders have been so displeased with Issa's efforts they decided to "move from him to another venue."
"Issa just is damaged goods," she said. "We've been there, done this, over and over again."
Issa has been highly critical of the Obama administration's response to the Sept. 11, 2012, attacks that killed U.S. Ambassador Christopher Stevens and three other Americans. The White House initially said the attacks were spontaneous and linked to protests earlier that day in Cairo against an American-made video denigrating Islam's prophet Muhammad. But Republicans have said the evidence shows that the administration knew it was a planned attack by an organized anti-American terrorist group.