In a sweeping raid, police arrested about a dozen men in the Toronto area on terrorism-related charges Friday night, the RCMP announced.

Intelligence sources allege the men were part of a terrorist cell, close to carrying out attacks on one or more Canadian targets.

Police seized chemicals used to make explosives and weapons.

"That's the tool of choice for anybody who wants to cause damage," a source who asked not to be named told The Canadian Press.

The suspects are either second-generation Canadians or recently immigrated to Canada with their families.

Sources claimed the men have no connection to al Qaeda, but were allegedly inspired by militant Islamic groups.

The arrests were made in co-operation with the Integrated National Security Enforcement Team, Cpl. Michele Paradis, a spokeswoman for the RCMP said in a release.

The operation involved at least four police forces, CSIS and the RCMP.

Undercover officers made the arrests, which were all carried out in the Greater Toronto Area.

"The investigation is ongoing," Paradis said Friday night.

Prime Minister Stephen Harper was made aware of the raid but did not comment. A spokesperson said Harper did not want to impede the operation as it unfolds.

The arrested suspects were reportedly being held in a police station in Pickering, a northeast suburb of Toronto.

Heavily-armed police officers kept guard outside the building Friday.

According to The Toronto Star, CSIS has monitored the suspects since 2004, while the RCMP began its investigation last year.

Sources discounted earlier reports that the CN Tower and the city's subway system were allegedly potential targets by the group.

More details about the arrests will be released during a Saturday news conference at 10 a.m. ET.

With files from The Canadian Press