RCMP Commissioner Giuliano Zaccardelli said in his resignation letter that he had always tried to be transparent and accurate in his dealing with the government. ((Tom Hanson/Canadian Press))

Giuliano Zaccardelli resigned as RCMP commissioner Wednesday, a day after admitting he gave incorrect testimony on the Maher Arar affair to a Commons committee.

The resignation came a day after Zaccardelli told the committee on public safety that he "made a mistake" in earlier testimony about the Mounties' involvement in the Ararcase.Following the apparentflip-flop, Harper expressed "concern" but said he wouldn't force out Zaccardelli without fully investigating.

On Wednesday afternoon, Harper told the House of Commons that Zaccardelli had quit.

"Today the RCMP commissioner offered me his letter of resignation and I have accepted it," Harper said.

"The commissioner has indicated to me that it would be in the best interests of the RCMP to have new leadership as this great organization faces challenges in the future."

Arar, a Canadian citizen who was born in Syria, wasstopped at a New York airport on his way home from a vacation in September 2002. U.S. officials accused him of links to al-Qaeda and deported him to Syria, where he was imprisoned and tortured for months.

Zaccardelli and the RCMPhave weatheredcriticism since September, when an inquiry into the case released a report that concluded the U.S. decision to deport Arar was "very likely" based on inaccurate and misleading information provided by the Mounties that suggested the Ottawa computer engineer was linked to the militants.

Always tried to be transparent, Zaccardelli says

In his letter of resignation, Zaccardelli said he had always tried to be transparent and accurate in his dealing with the government and "do what is in the best interest of the Canadian public, the RCMP and the institutions of Government."

'My recent attempt to set the record straight and correct misperceptions I helped create has stirred new controversy.' -Giuliano Zaccardelli in his resignation letter

"I must take responsibility for having added to the confusion in my first appearance before the Parliamentary Committee," he wrote.

"My recent attempt to set the record straight and correct misperceptions I helped create has stirred new controversy.

"The continuing controversy, however, makes it increasingly difficult for me and for the institution to fulfill its responsibilities to the Canadian people."

'Set the record straight'

While appearing before the committee on Tuesday, Zaccardelli said he got his facts wrong when he testified on Sept. 28 about when he first knew the RCMP had passed incorrect information about Arar.

In September, Zaccardelli acknowledged the Mounties under his watch made mistakes in the Arar case, including by providing the erroneous information.

However, he also repeatedly told the legislators that the RCMP contacted U.S. officials to correct the record before Arar was deported. Zaccardelli also said he had learned of the erroneous information while Arar was still in a Syrian prison.

However,Zaccardelli offered a different timeline when he reappeared before the committee on Tuesday.

He said the Mounties had not tried to correct the record while Arar was still in the United States and that he didn't learn about the case until 2006.

Zaccardelli, who first publicly disclosed the new account on Monday during a speech in Ottawa, said he learned a lot more about the involvement of the RCMP after the inquiry released its report.

Arar's lawyer calls for wider accountability

Opposition politicians had been calling for Zaccardelli's dismissal since Justice Dennis O'Connor released the inquiry's report on Sept. 18 — and those calls have dominated question period for the past two days.

'Obviously, accountability starts at the top, but it doesn't end there.' -Lorne Waldman, Maher Arar's lawyer

But news of Zaccardelli's resignationdid not silence the opposition, which slammed government ministers who said they were only made aware of the revised testimonyon Tuesday.

Lorne Waldman, Arar's lawyer, said Zaccardelli's resignation shouldn't mark the end of the investigation because he was only one individual, whereas many RCMP officials handled in the Arar file.

"Obviously, accountability starts at the top, but it doesn't end there," Waldman told CBC News on Wednesday.

"So far we have not had any indication that any of the other individuals involved were disciplined. Indeed, we've been told that they've been promoted."