Three Ontario men, from left to right, Khurram Sher, Hiva Alizadeh and Misbahuddin Ahmed, have been charged in connection with an alleged domestic terrorism plot. (Sarah Wallace/CBC)

Police believe one of three Ontario men charged in connection with an alleged terrorism plot travelled to Pakistan seeking terrorist training, sources have told CBC News.

A state source in Pakistan and a source in Canada familiar with the investigation told CBC News that police believe it was the alleged ring leader, Hiva Mohammad Alizadeh, who travelled to Pakistan seeking the training.

Alizadeh, 30, Misbahuddin Ahmed, 26, both of Ottawa, and Khurram Syed Sher, 28, of London, Ont., are accused of conspiring to facilitate terrorism with others in Canada, Afghanistan, Iran, Pakistan and Dubai over the past two years.

Alizadeh is also charged with possessing an explosive substance with intent to harm and providing property or financial services for the benefit of a terrorist group.

Investigators say they seized more than 50 improvised bomb detonators stashed in the closet of his Ottawa apartment.

Police also accuse Alizadeh of providing support to terrorism with co-conspirators in Iran, Afghanistan, Dubai and Pakistan.

During a news conference last week, police alleged one of the suspects had training in improvised explosive devices (IED) and singled out Alizadeh, accusing him of being a member of a terrorist group with links to the conflict in Afghanistan.

CBC sources point to groups based in Pakistan. Pakistani newspapers, citing their own sources, believe there are links to the Tehrik-e-Taliban — the same group behind the attempted bombing of New York's Times Square in May.

None of the allegations against the Canadian men accused in this latest case have been tested in court.

CBC News called and emailed Alizadeh's lawyer about the alleged ties to Pakistan but received no comment.