Former National Security Adviser H.R. McMaster on Thursday reacted to Russia’s escalated invasion of Ukraine.

McMaster warned on CBS’s “Mornings” that Russian President Vladimir Putin will continue to escalate until he “is met with strength.”

“[Putin has] already threatened nuclear war,” McMaster emphasized. “And so, I think what we have to see is this latest assault in a broader context. I mean, just think about what he’s done since 2007: massive cyberattacks on Estonia, the invasion of Georgia in 2008, the constant, you know, undermining of Ukraine, poisoning presidential candidates, for example, assassinations. It’s not going to be the end of it. What we’ve seen in recent days is the weaponization of migrants on the border in weeks with Poland, encouraging Serbian separatists in the Balkans to reignite conflict there. Once you get into Ukraine — look at Moldova.”

“This is going to go on and on until Putin is met with strength,” he added. “He will push as far as he can. And I think it’s extremely important that we maintain the unity we have seen so far, and I think we ought to applaud the Biden administration’s effort to keep the family together, with the U.S, U.K., the European Union and Canada, I think, responding together well and really across the free world.”

Follow Trent Baker on Twitter @MagnifiTrent