Tom Flanagan, a former senior adviser to Prime Minister Stephen Harper, says he regrets his "glib" comment calling for the assassination of WikiLeaks founder Julian Assange.

"It was a thoughtless, glib remark about a serious subject," Flanagan said Wednesday on the CBC's Power & Politics with Evan Solomon.

"I never seriously intended to advocate or propose the assassination of Mr. Assange. But I do think that what he's doing is very malicious and harmful to diplomacy and endangering people's lives, and I think it should be stopped."

Earlier, Flanagan said in a statement to CBC News, "If Mr. Assange is arrested on the recently announced Interpol warrant, I hope [he] receives a fair trial and due process of law."

But Mark Stephens, Assange's lawyer, told Power & Politics that Flanagan's comments are "a matter for the Candian authorities, as a criminal offence — the incitement to kill — has been committed on their soil."

In a panel interview Monday night on Power & Politics, Flanagan said U.S. President Barack Obama "should put out a contract and maybe use a drone or something."

Tom Flanagan says he 'wouldn't be unhappy' if WikiLeaks founder Julian Assange 'disappeared.' (CBC)

"I think Assange should be assassinated, actually," Flanagan said with a laugh, and when asked to expand upon his answer, added that he "wouldn't be unhappy" if Assange "disappeared."

When the CBC's Solomon commented that his position was "pretty harsh stuff," Flanagan, who is known for his off-the-cuff sense of humour and often brings props to panel interviews, replied, "I'm feeling very manly today, Evan."

Although Flanagan described most of the information in the leaked U.S. cables as "harmless," he added the revelation that Arab diplomats requested the U.S. to attack Iran's nuclear facilities as secrets that "could conceivably lead to war."

"This is really not stuff that should be out," he said.

Flanagan, a University of Calgary professor who previously served as Harper's chief of staff, is no stranger to controversy and has often been at odds with his former boss and colleagues in the Conservative caucus in recent years.

Comments 'obviously tongue-in-cheek': Reid

Scott Reid, a former Liberal adviser to prime minister Paul Martin who was on the TV program's panel with Flanagan, said he believed Flanagan was being "his usual colourful and provocative self " and was "obviously talking tongue-in-cheek."

"Not for a second did I think he was suggesting seriously that someone's life be put at risk," said Reid. "He's a great guy with strong opinions, not a mean guy with lunatic opinions."

Later on Wednesday, New Democrat Paul Dewar asked the government about Flanagan's comments during question period in the House of Commons.

"Mr. Flanagan speaks for himself," Government House Leader John Baird responded. "He doesn't speak for the government and he hasn't advised the PM for years. I certainly don't share his views."

Liberal MP Denis Coderre has filed an official complaint with the CBC's ombudsman Vince Carlin regarding what he called a "declaration to incite violence."

A number of U.S. and Canadian media figures have either suggested or demanded Assange be targeted for assassination or executed in the wake of the embarrassing scandal over the hundreds of thousands of secret diplomatic messages being published online. Amid the furor, Assange's whereabouts remain unknown.

Former U.S. Republican vice-presidential candidate Sarah Palin, who is widely expected to run for president in 2012, has called the former computer hacker an "anti-American operative with blood on his hands" and accused Obama of not doing enough to stop the WikiLeaks founder.

"Why was he not pursued with the same urgency we pursue al-Qaeda and Taliban leaders?" she said.

Canadian author and columnist Ezra Levant questioned why the Obama administration has treated the Australian-born Assange differently than the Taliban leaders targeted for assassination, saying he and his WikiLeaks colleagues "act like spies, not journalists."

"Why is Assange still alive?" Levant wrote in his column for QMI Agency earlier this week.

"Why is he being treated as a journalist or political activist? If someone had published the intimate details of the D-Day plans during the Second World War, he would never have been seen again."

Meanwhile, Interpol has placed Assange on its most-wanted list after Sweden issued an arrest warrant against him as part of a drawn-out rape investigation.

Assange, whose whereabouts are unknown, is suspected of rape, sexual molestation and unlawful coercion. He has denied the allegations, which stem from his encounters with two women during a visit to Sweden in August.

With files from The Associated Press