Former U.S. secretary of state Hillary Clinton says Canada has an important role to play in NATO as the alliance braces for more developments linked to the crisis between Russia and Ukraine.

Speaking in Montreal, Clinton says Canada and the U.S. should work together to find a smart solution to deter further aggression or even a conflict that gets out of control.

She says the neighbours must remain closely unified as they prepare for what she describes as “probing and testing” by Russian President Vladimir Putin.

Clinton warns that Putin’s rationale for annexing the Crimean Peninsula because it’s home to ethnic Russians and Russian speakers could be extended not only to other parts of Ukraine, but to other countries like Estonia, Lithuania and Latvia.

The potential 2016 U.S. presidential contender calls the crisis a clash of values and an effort by Putin to rewrite the boundaries of post-Second World War Europe.

Earlier Tuesday, Foreign Affairs Minister John Baird announced new sanctions against Russia as he slammed Putin over the “illegal annexation” of Crimea.