Canadian authorities said they arrested a man Tuesday as he tried to leave for Somalia to join the al-Shabaab terrorist organization.

Mohamed Hersi, 25, was arrested at Toronto Pearson International Airport as he was about to board a plane to Cairo through London. After arriving in Egypt, the former University of Toronto health sciences student planned to go to Somalia "to join Al-Shabaab and participate in their terrorist activities," the Royal Canadian Mounted Police (RCMP) said.

Hersi is charged with planning to participate in terrorist activities and counseling an unidentified person to do the same.

Just over two years ago, the RCMP and the Canadian Security Intelligence Service stepped up investigations of Somali jihadist recruitment in the wake of reports that Toronto men were traveling oversees to join al-Shabaab.

Previous terrorism cases in Canada were brought to the attention of the RCMP through foreign allies and intelligence agencies, Canadian officials said. In contrast, the Hersi investigation resulted from the efforts of the Toronto Police, who received a lead months ago and followed up. Once city police detectives concluded there was a genuine security threat, the RCMP was brought in to investigate.

Al-Shabaab has been increasingly active in its recruiting efforts in the Toronto area, home to tens of thousands of Somali-Canadians. Omar Hammami, a Muslim convert and U.S. native, lived in Toronto before traveling to Somalia and becoming one of the jihadist group's senior military leaders. Watch here as Mohamed Abdullahi Mohamed, a Somali-Canadian who spent six months training alongside al-Shabaab, describes his "nightmare" – the possibility that other radicalized, disaffected Somalis will leave Canada, travel to training camps in Somalia, and return to Canada to carry out attacks.