Defence chief Gen. Jonathan Vance says the military first became aware of a Manitoba reservist's alleged links to a neo-Nazi group in the spring and were investigating him in earnest weeks before media reported on the matter.

The comments mark the first time Canada's top general has spoken about Master Cpl. Patrik Mathews.

Vance says the military's counter-intelligence unit was first alerted to Mathews in April, at which point the combat engineer with the 38 Canadian Brigade Group in Winnipeg met with local commanders.

The defence chief says Mathews subsequently applied to leave the Forces even as military officials launched an investigation into his activities — a probe Vance says was underway by July, weeks before the Winnipeg Free Press published a story about the reservist.

Mathews has not been arrested or charged with any crime, and Vance isn't providing further details, citing privacy laws and the ongoing investigation.

Vance says the Forces will not tolerate anyone who wants to use the military as a training ground or avenue to spread hate and discrimination.