Ottawa will place a Yemen-based al Qaeda offshoot on Canada's official terror watch list Thursday, CTV News has learned.

The group, known as al Qaeda of the Arabian Peninsula, has been linked to several unsuccessful terror attacks, including last October's two attempted bombings of planes using printer toner cartridges and last December's failed "underwear bomber."

Placing them on the official list will make it illegal for any Canadian to deal with the group, at home or abroad.

It has been reported recently that the group was considering a new tactic -- poisoning the American food supply.

U.S Homeland Security said it's credible the group could poison easily accessible food like a salad bar using cyanide or ricin.

"If you've got someone employed in the food service business, you could put those guys anywhere," Dr. Gaylord Lopez of the Georgia Poison Center said.

However, Homeland Security officials played down the threat, saying it was similar to many other ideas posted online on jihadist websites.

"We're talking months, not weeks (ago), that this came into the threat stream," an official told CNN Tuesday.

The RCMP has also played down the threat to Canada, but said their anti-terror officials are working overtime during the busy holiday season.

"That is not the type of threat that I'm aware of that exists here in Canada. However, we never know the tactics they will use, they are very ingenious," RCMP Assistant Commissioner Gilles Michaud told CTV News.

The RCMP are worried that al Qaeda could attempt a strike over the holiday season, as they did last December,

"We are seeing an increase in the noise activity as to the threat indications," Michaud said. "The threat is definitely real in Canada … Definitely over the holidays we do not pack our bags and go home."

Al Qaeda of the Arabian Peninsula is led by the U.S.-born Anwar al-Awlaki.

Al-Awlaki, a former imam, is said to have inspired accused Fort Hood shooter Nidal Malik Hasan and the attempted Times Square bomber, Faisal Shahzad.

The Obama administration has authorized the targeting killing of Al-Awlaki, making him the first American citizen to be put on the list of terror suspects the CIA is allowed to kill.

With a report from CTV Ottawa Bureau Chief Robert Fife