Pentagon press secretary John Kirby spoke to reporters Friday on the U.S. military's plans to aid Ukraine as Russian forces continue to advance through the country.

One reporter asked Kirby if U.S. intelligence suggests Russian President Vladimir Putin would stop his advancement with Ukraine. Some European countries are anxious that the Russian president's campaign could continue past the borders of the war-torn country. 

"It is not entirely clear if Mr. Putin has designs beyond the Ukraine," Kirby said. "And it's because that's not perfectly clear that we continue to look for ways to bolster our NATO capabilities and to reassure our allies. I mean, one of the reasons we're doing this is because we want to make it clear to him that we will defend every inch of NATO territory."

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"I think there's no reason for it to be a war now," Kirby told reporters on the possibility of a full-on armed conflict between NATO forces and Russia. "And it shouldn't have been. Mr. Putin had diplomatic options on the table that he decided to ignore and to evade and to invade Ukraine regardless. So there should be no reason why there's a war."

Kirby, however, warned that with Putin's war on the Ukraine already underway, it was paramount for the U.S. to make clear to the Russians that it would defend "every inch of NATO territory."

"We need to make sure – and we will make sure – that it's very clear that we're going to defend every inch of NATO territory," Kirby repeated. "I'm not going to speculate about what the future holds because it is not perfectly clear where Mr. Putin is going here. We want to make it clear that he will not be able to threaten in any tangible way our NATO allies."

refugee center

A humanitarian center for refugees coming from Ukraine at the Moldovan-Ukrainian border, in Palalanca, Moldova, Friday, Feb. 25, 2022. Thousands of Ukrainians are fleeing from war by crossing their borders to the west in search of safety. They left their country as Russia pounded their capital and other cities with airstrikes for a second day on Friday. Cars were backed up for several miles at some border crossings as authorities in Poland, Slovakia, Hungary, Romania and Moldova mobilized to receive them, offering them shelter, food and legal help.  (AP Photo/Aurel Obreja)

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White House press secretary Jen Psaki said the Biden White House has not "ruled out diplomacy forever" with Russia amid the Kremlin’s invasion of Ukraine.

Psaki said the U.S. would not be completely icing out the Eastern European aggressor "forever" during the White House daily press briefing Friday.

Ukrainian servicement

Ukrainian servicemen stand near a destroyed house near the front-line village of Krymske, Luhansk region, in eastern Ukraine, Saturday, Feb. 19, 2022.  (AP Photo/Vadim Ghirda)

Psaki was also asked why President Biden and Russian President Vladimir Putin were not talking.

"Because (Putin's) invading a sovereign country," she replied.

"I would say that a moment where a leader is beginning and in the middle of invading a sovereign country is not the moment where diplomacy feels appropriate," Psaki added.

"It does not mean we have not ruled out diplomacy forever. Obviously the president remains open to engaging on a leader-to-leader level, but this is not the moment."

Psaki also said the U.S. was "not in a business-as-usual moment" amid the Russian invasion of Ukraine.

Psaki also confirmed the U.S. will join the European Union in sanctioning Russian President Vladimir Putin personally over the invasion of Ukraine.

Fox News' Houston Keene contributed to this report.