I'm Wolf Blitzer. This is CNN tonight. We want to welcome our viewers here in the United States and around the world.

I'm not walking anything back. That vow from President Biden today, getting defensive in his first extensive explanation of his ad lib heard around the world this weekend.

For God's sake, this man cannot remain power.

That remark about Vladimir Putin at the close of President Biden's address in Poland on Saturday has been looming over his White House ever since its has some aid scrambling to counter interpretations.

The president was signaling the US would be actively seeking regime change in Russia, but he says that's not what he meant.

I'm not walking anything back. I wasn't then nor am I now, articulated a policy change. I was expressing more outrage that I feel and I make no apologies for it.

Nobody believes we're going to take down. I was going to was talking about taking down Putin.

The last thing I want to do is engage in a land war or nuclear war with Russia. It's more an aspiration than anything he shouldn't be in power.

There's no I mean, people like this shouldn't be rolling countries, but they do. The fact they do, but doesn't mean I can't express my outrage about it.

The president says he wasn't talking about taking Putin down, though his rhetoric on Russia's leader has only been tuffeting by the day.

He's now called Putin and I'm quoting him at butcher, a killer, a war criminal, a brute, a pure thug, a murderous dictator and someone who cannot be in power.

He changed that today too. Shouldn't be in power, but should President Biden stay away from that kind of language?

We're going to get the take of a former NATO Supreme Allied commander in just a moment. First, though, to the very latest on Russia's brutal invasion,

shelling intensified around the suburbs of the Ukrainian capital of Kiev today. A defense official there says Russian forces are attempting to block supply routes.

New drone footage shows how viciously the Russians are continuing to attack the port city of Mariapol in the southeast.

These are more destroyed buildings and homes after very heavy fighting. Russian forces consolidated control around the city, but Ukraine's military says it is maintaining a so-called circular defense.

A Mariapol city official will also be with us tonight with what he's hearing, standby for that. Meanwhile, Russia is also continuing missile strikes in Western Ukraine, including the city of Lutz.

That's where massive fires have been raging. The next round of talks between the two countries will be held tomorrow in Turkey, but there is certainly no peace or any ceasefire in the meantime tonight.

That's good to see you, our senior international correspondent Fred Plyknev, joining us now from Kiev, the capital.

As we hear these reports from Ukraine's Deputy Defense Minister, that Russian forces are trying to block supply routes to the capital.

What does that increase in shelling look like on the ground? You're there.

Well, it's pretty constant. I would say that the operations that we see here on the ground certainly have picked up pace. It's been quite interesting over the past week or so, Wolf.

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