Liberal Leader Michael Ignatieff is keeping the pressure on Conservative Leader Stephen Harper, writing an open letter to demand a one-on-one leaders' debate.

Ignatieff published the open letter on the Liberal Party's website Friday morning.

"As you stated, there are only two people who can be prime minister after May 2nd: you or me," Ignatieff wrote. "Canadians truly deserve to see us go face to face in a contest of ideas, values and very different visions for our country. That is what democracy is all about.

"Like many Canadians, I was disappointed and puzzled when you reversed your commitment, and tried to back out yesterday. I don't understand why you have gone back on your word, or why you would wish to disappoint Canadians."

Again Friday, the election campaign has been sidetracked by the question of a televised leaders' debate. Ignatieff and Harper had both accepted each other's challenge on Wednesday for a one-on-one debate.

Harper then seemed to distance himself from that commitment on Thursday, when he said he was interested in one leaders' debate.

Harper continued to say that he preferred a one-on-one debate with his chief rival but the discussion is now over.

"Our position (was) that we were open to a whole range of debate formats and we would accept the judgment of the networks in the end. And that is exactly what we've done," Harper said during a news conference in Dieppe, N.B.

"We didn't get the preference we want. If other parties had wanted a different preference than what they got they should have said so when we were having those negotiations."

Despite Harper's statements on Friday, Ignatieff is still trying to provoke his chief rival into accepting an additional one-on-one.

"Perhaps I can make this easier for you. I will meet you at the time and place of your choosing," Ignatieff's letter said.

"There is no need for complicated or convoluted debate formats. Just two podiums — and you and me. A true, honest-to-goodness battle of ideas and visions."

NDP Leader Jack Layton continued to criticize Ignatieff's proposal for a separate debate.

Layton said during a news conference Friday that the election is a race for prime minister among all the parties, and the Liberal leader cannot pick who he gets to debate with.

"I think Mr. Ignatieff is showing that he isn't a true democrat, that he actually wants to exclude people from the national discussion who have every right to be there," Layton said.

"I think that should concern everybody."

Organizations offer to host debate

Several different organizations have stepped up with offers to host a debate between Harper and Ignatieff.

CBC News The National has invited leaders of the Liberal and Conservative parties for a one-on-one debate, hosted by Peter Mansbridge, the CBC's chief correspondent.

Additionally, Don Newman, the advisory board chair of Canada 2020, has also offered to host a 90-minute, bilingual debate within a week after the already-planned leaders' debate.

The broadcast consortium is comprised of representatives of CBC/Radio-Canada, CTV, Global and TVA. It announced on Wednesday night that the English television debate will take place on April 12. Meanwhile, the French debate will take place on April 14. Both debates will take place in Ottawa.

Both NDP Leader Jack Layton and Bloc Québécois Leader Gilles Duceppe have dismissed the idea of a one-on-one debate between Harper and Ignatieff.