MONTREAL — Former US secretary of state Hillary Clinton on Tuesday accused Russian President Vladimir Putin of attempting to “rewrite the boundaries” of post-World War II Europe.

She warned that other countries near Russia could also face aggression if Putin is allowed to get away with his move to annex Crimea, which Clinton called illegal and a violation of international law.

“If he’s allowed to get away with that, I think you’ll see a lot of other countries either directly facing Russian aggression or suborned with their political systems so that they are so intimidated that in effect they are transformed into vassals, not sovereign democracies,” she said at an event hosted by the Board of Trade of Metropolitan Montreal at the Palais des Congres.

Clinton’s critique came as Putin signed a treaty claiming the Black Sea region of Crimea as Russian territory, as Ukraine warned the showdown had entered a “military stage” after soldiers were killed on both sides.

The treaty signing was conducted at lightning speed in the Kremlin in a defiant expansion of Russia’s post-Soviet borders that has plunged relations with the West to a new post-Cold War low.

“We’ve got to do a better job in supporting the government in Kiev, we’ve got to do a better job in getting Europe to do more for themselves when it comes to energy so they’re not dependent,” said Clinton, a potential 2016 Democratic US presidential candidate.

“It’s an effort by Putin to rewrite the boundaries of post-World War II Europe,” Clinton, also a former US first lady, told a conference organized by the Board of Trade of Metropolitan Montreal, to applause.

“I hope there’s not another Cold War, obviously nobody wants to see that. Primarily, it’s up to Putin.”

Russian President Vladimir Putin addresses the Federation Council in Moscow's Kremlin on Tuesday, March 18, 2014. (photo credit: AP/Alexander Zemlianichenko)

Russian President Vladimir Putin addresses the Federation Council in Moscow’s Kremlin on Tuesday, March 18, 2014. (photo credit: AP/Alexander Zemlianichenko)

She advocated for a “two-track” approach toward resolving the crisis that included economic incentives and “standing up for our values.” She also said Europe needs to be encouraged to find other energy sources so they aren’t dependent on Russian oil and gas.

Clinton, who narrowly lost the Democratic nomination in 2008, added: “The rationale that Putin uses (in Crimea) — that they were ethnic Russians, Russian speakers, that they’ve always been part of Russia — it could be extended not only to other parts of Ukraine but also to other parts of Estonia, Lithuania, Latvia, Transnistria.

“There are a lot of places where there are ethnic Russians and Russian speakers.”

Asked whether she would run for the White House, Clinton replied: “I haven’t made up my mind, besides I feel a deep sense of commitment to my country and its future. I feel an obligation to do all I can for the children of my country.”