Newt Gingrich, a potential 2012 Republican presidential contender, said Sunday he would not participate in a debate moderated by Keith Olbermann or Chris Matthews.

“There's no possibility that I would ever go to a debate and have Olbermann or Chris Matthews asking questions,” Gingrich said on C-SPAN’s "Washington Journal."

The former House Speaker said he thought the two cable channel hosts were biased against Republican candidates while they favored their Democratic counterparts. He called the two “relentlessly hostile” and “so left-wing.”

“I watched the debate a couple of years ago and it was an embarrassment because they were so relentlessly hostile and they were so left-wing that every question they asked of the Republicans was designed to embarrass and divide the Republicans. And every question they asked the Democrats was designed to make them look good. Well, why would we participate in that?” Gingrich said.

Though Olbermann and Matthews did not moderate any of the three 2008 general election debates between President Obama and Sen. John McCain (R-Ariz.), they did moderate some debates during both parties’ presidential nominating contests.

For example, Matthews moderated some Republican-only candidate debates in 2007. Olbermann also moderated a forum for Democratic candidates sponsored by the AFL-CIO that same year.