Freeland issued the warning during a news conference in Ottawa today, where she announced further sanctions against Russia over its invasion of Ukraine.
The deputy prime minister said Canada believes Russia’s attack is illegal, implying anyone fighting for the Russian side could be breaking international law.
Defence Minister Anita Anand, however, acknowledged there are uncertainties around whether it is legal for Canadians to fight for the Ukrainian side.
Many Canadians have been answering the Ukrainian government’s call for volunteers to join an “international brigade” to help defend the country.
Anand instead encouraged people to enlist with the Canadian Armed Forces, which is in the midst of a recruitment drive as it deals with a shortfall of thousands of service members.