NATO chief Jens Stoltenberg denounced on Friday the "brutal" Russian invasion of Ukraine, and condemned attacks on civilians and on the Zaporizhzhia nuclear power plant in Enerhodar, southeastern Ukraine.

"We condemn the attacks on civilians. And over the night, we have also seen reports about the attack against the nuclear power plant," Stoltenberg said in a joint press conference with US Secretary of State Antony Blinken, ahead of a meeting with Western foreign ministers in Brussels.

“This just demonstrates the recklessness of this war and the importance of ending it and the importance of Russia withdrawing all its troops and engaging good faith in diplomatic efforts," Stoltenberg added.

He said that while NATO allies have "implemented unprecedented sanctions" on Russia and provided "support" to Ukraine, "NATO is not part of the conflict."

"At the same time, we need to make sure that there is no misunderstanding about our commitment to defend and protect all Allies."

He said that NATO forces have increased their "defensive presence" in the eastern part of the Alliance.

Stoltenberg also called on the US, Europe and Canada for support.

"I welcome the strong commitment from the United States with more troops," he said.

"I met many of them. And it is always great to meet US troops in Europe and to see their commitment, and their professionalism, being part of the transatlantic bond.

"I also welcome that European Allies and Canada are stepping up with more presence in the eastern part of the Alliance, on land, at sea and in the air.

"If anything, I think the crisis we are faced with now demonstrates the importance of North America standing together in strategic solidarity in NATO," he added.

Also reacting to the attack, UK Deputy Prime Minister Dominic Raab told BBC Breakfast, “It’s very difficult to believe that it wasn’t done deliberately. But in any event, it is unlawful to attack a site like this and not to do your due diligence on it and to keep bombarding it.”

Russian forces have occupied Ukraine's Zaporizhzhia nuclear power plant following a fire at the facility early on Friday, Ukrainian authorities have said.

The fire was extinguished in the early hours of Friday morning.

CNN