A man from Toronto is believed to be among a group of medical students and doctors who have crossed from Turkey into ISIS-controlled territory in Syria.

Ismail Hamdoun is believed to have entered into Syria with the group on March 13, according to Turkish officials.

Hamdoun's father, Ibrahim, told CTV News' Daniele Hamamdjian that his son is between 26 to 28 years old, and is a Canadian citizen who graduated from medical school in Sudan.

The others in the group of 11 people include seven British citizens, one American, and two Sudanese nationals, Turkish opposition lawmaker Mehmet Ali Ediboglu said Monday.

The group is believed to be in Syria, working to treat the wounded in hospital, Hamamdjian said.

Nicholson: Terrorism remains a threat

Foreign Affairs Minister Rob Nicholson said Monday he had few details about Hamdoun, and declined to confirm reports he had joined ISIS. However, Nicholson said Canadians must be on guard against homegrown terror threats.

“It underlines the fact that terrorism is a threat right here at home and abroad, and this is why Canada has to continue to fight terrorism at home and abroad,” Nicholson told reporters.

When asked whether it made a difference that Hamdoun is believed to have travelled to Syria not to fight, but to work as a doctor, Nicholson seemed to suggest it made little difference.

“We’re not in the business of supporting ISIS and this is the reason we are in Iraq and why this mission is going to continue,” Nicholson said. 

Hamdoun's father is in Turkey trying to get more information about his son, who he said had previously told him of his intentions to travel there.

Some of the students' parents have released a statement, claiming that their children had travelled to Turkey to do humanitarian work. They also called on their home governments to work to "ensure the safety" of their children, and bring them back home as soon as possible.

The Home Office in the U.K. has said that if the British nationals return home, and can prove that they were only working on humanitarian positions, they may not face charges.

Canadian could face harsh punishment back in Canada

However, the situation could be very different if Hamdoun returns to Canada, said CTV’s Richard Madan.

“In Canada it’s a whole different story if these allegations are true,” Madan told CTV News Channel. “A spokesman from Public Safety told CTV if indeed Mr. Hamdoun does return home to Canadian soil, they would essentially throw the book at him under existing law.”

Under current laws contained in the Criminal Code of Canada, “providing or offering to provide a skill or an expertise for the benefit of, at the direction of or in association with a terrorist group,” is against the law with a maximum sentence of 10 years.

The Conservative government recently introduced their controversial Bill C-51 anti-terrorism legislation, which has not yet passed, but which would significantly beef up the tools available to law enforcement agencies to combat terrorism.

The anti-terror legislation would give CSIS the ability to actively disrupt terror plots, expand no-fly list powers and allow police to have greater control in limiting the movement of a suspect.

The bill would also allow for increased intelligence-sharing between law-enforcement authorities.

In a statement to CTV News, a spokesperson for Public Safety Minister Steven Blaney said the government is taking steps to fight any terrorist threat to Canada.

"Our government made it a criminal offence to go overseas to engage in terrorism and we will revoke the citizenship of dual nationals convicted of terrorism," the statement said.

With files from CTV's Daniele Hamamdjian and The Associated Press