Stéphane Dion has apparently apologized Thursday for saying the prime minister's spokesman was involved in extortion, the same day the spokesman accused the Liberal leader of defaming him.

Dimitri Soudas, a spokesman for Prime Minister Stephen Harper, was fingered for political interference in media reports published earlier this week.

In a letter released Thursday, Soudas's lawyer said Dion, who accused Soudas of being involved in extortion, owed the man a public apology and had until next Wednesday to deliver it to the media outside of the House of Commons.

It was not immediately clear if an apology made by Dion after question period Thursday would suffice.

"Yesterday I used an inappropriate word: 'extortion' attempt. I apologize for that, and that was not the appropriate word," Dion said.

Instead, he said the situation sounded like political interference.

Soudas and Leo Housakos, a longtime Tory supporter and party organizer in Quebec, were the subjects this week of a joint investigation by the Globe and Mail and Radio-Canada.

The report, which aired on the CBC's French-language service Tuesday night, alleged Soudas directly intervened on behalf of Rosdev Group, a Montreal real estate developer currently involved in a multimillion-dollar lawsuit with the Public Works Department over the management of two office buildings that house thousands of civil servants.

The report also said that Housakos intervened directly with the Public Works Department.

The allegations have created a stir in the House of Commons. The NDP have called for an investigation by the federal ethics commissioner, while the Bloc Quebecois have tabled a motion that would require Soudas to appear before a parliamentary committee.

Soudas denies allegations

Soudas has denied that he was guilty of political interference, saying he consulted with Public Works in order to get information about the lawsuit.

"Your allegation that Mr. Soudas was party to extortion … is patently false," said the letter to Dion from the Lang Michener firm.

"At no time did our client act illegally or use an official position or powers to obtain property, funds, or patronage.

"Your defamatory statement was calculated to maliciously disparage our client as a person and as a public official, and is actionable as such."  

With files from the Canadian Press