MONTREAL — Two Montreal women, ages 18 and 19, were reported missing by their families in November and Canadian authorities believe they have joined Islamic State (ISIS) in Syria.

Police fear the women have become "slaves" of jihadist fighters, said Insp. Andre-Guy Lamothe of the Montreal police anti-terrorism unit.

"There were signs of radicalization," he said. "Unfortunately, we lost them, they've already arrived there. They'll be used as slaves for the people there."

Lamothe wouldn't say exactly where he believes they went.

Both Montrealers are considered high-risk travellers and are being investigated by Canada's Integrated National Security Enforcement Teams, a source close to the investigation told QMI Agency. The two women are friends.

The Criminal Code bars any Canadian from joining terrorist groups such as ISIS or providing money or assistance of any kind.

At the request of police, QMI Agency isn't revealing the women's names to prevent others in their inner circle from becoming radicalized. Police say they have a close relationship with the grieving families.

A CSIS agent told QMI that 10% to 15% of young people who leave their families to join ISIS are women.

"Radicalization used to take three, four or five years," the agent said. "Now we're talking about months."

He recalled holding sobbing parents in his arms after informing them that their children left to fight with terrorists.

"I've met many parents and it's sad," the spy said. "They didn't know. It's too late. They're gone."

He said people can become radicalized in front of their computers and recruitment can take just a few weeks.

"We couldn't detect them," he said.

RCMP Sgt. Hakim Bellal, head of a community outreach program on radicalization and national security, has also seen firsthand how families are affected by the radicalization of their children.

"The families are the victims," he said. "They don't even know their children are gone (to Iraq or Syria). They think they're just missing."

Last fall, the head of Canada's spy agency said authorities are monitoring 80 suspected Canadian terrorists who have returned home from violent hot spots around the world.

Montreal police officers discussed the foreign fighter problem this week at a special training session on terrorism and radicalization.

The session, organized by the RCMP, also included Quebec provincial police and intelligence agents. About 100 officers received the training.