President Joe Biden attended an emergency NATO summit Friday morning from the White House Situation Room to coordinate next steps with Western allies as Russian President Vladimir Putin wages a full-scale invasion of Ukraine.

       Biden said in an address Thursday that NATO would meet to "affirm our solidarity and to map out the next steps we will take to further strengthen all aspects of our NATO alliance."

       He also announced escalated sanctions to correspond with the escalated Russian aggression, but not the full economic punishment Ukraine and others have called for and none yet on Putin himself, although he did say that option was "not a bluff. It's on the table."

       MORE: Biden announces new sanctions on Russian banks, elites but not yet on Putin himself

       The White House

       President Biden convened a meeting of the National Security Council in the White House Situation Room to discuss the unprovoked and unjustified attack on Ukraine, on Feb. 24, 2022 in Washington, D.C., in an image released by The White House.

       "He has much larger ambitions than Ukraine," Biden warned of the Russian leader. "He wants to, in fact, reestablish the former Soviet Union. That's what this is about. And I think that his ambitions are completely contrary to the place where the rest of the world has arrived."

       Pressed on why the U.S. hasn't gone further with sanctions, Biden said that some decisions must be made in unison with European allies -- signaling more sanctions may follow Friday's meeting of NATO's 30 member countries.

       MORE: How NATO factors into the Ukraine-Russia conflict

       "The sanctions that we are proposing on all their banks have the equal consequence, maybe more consequence than SWIFT, number one. Number two, it is always an option but right now that's not the position that the rest of Europe wishes to take," Biden said, referring to an international messaging system that allows large financial institutions to send money to each other.

       Olivier Matthys/AP

       NATO Secretary General Jens Stoltenberg speaks during a media conference after a meeting of the NATO-Ukraine Commission at NATO headquarters in Brussels, Tuesday, Feb. 22, 2022.

       NATO Secretary-General Jens Stoltenberg offered public remarks to open the meeting and will hold a news conference at its conclusion, which will be live-streamed on ABC News Live.

       "Russia has shattered peace on the European continent," he began. "What we have warned against for months has come to pass, despite all our efforts to find a diplomatic solution. Moscow bears sole responsibility for the deliberate, cold-blooded and long-planned invasion."

       MORE: Why Americans should care about the Ukraine-Russia conflict

       Stoltenberg said NATO condemns Russia's aggression "in the strongest possible terms" and is calling on Russia to "immediately cease its military action."

       "We stand with the brave people of Ukraine. We fully support Ukraine's sovereignty and territorial integrity, its right of self-defense, and its right to choose its own path," he added.

       Manu Fernandez/AP

       A protestor holds a banner depicting Russian President Vladimir Putin during a demonstration in front of the Russian Embassy in Madrid, Feb. 24, 2022. Russia launched a wide-ranging attack on Ukraine on Thursday, hitting cities and bases with airstrikes or shelling, as civilians piled into trains and cars to flee.

       Biden reiterated on Thursday that U.S. troops would not be involved in the fight against Russia in Ukraine, but he did announce that he will deploy more forces to Germany, including some of the 8,500 troops in the U.S. that have been on a "heightened alert," and said he is open to sending additional troops elsewhere in Europe.

       "Our forces are not going to Europe to fight in Ukraine but to defend our NATO allies and reassure those allies in the East," Biden said. "As I made crystal clear, the United States will defend every inch of NATO territory with the full force of American power."

       MORE: Ukrainians in US fear for loved ones back home amid Russian invasion

       Throughout the crisis, Biden has maintained U.S. involvement is about fulfilling a responsibility to defend NATO allies -- and democracy around the world.

       "America stands up to bullies," Biden said Thursday. "We stand up for freedom. This is who we are."

       ABC News' Luis Martinez contributed to this report.