President Joe Biden on Monday reacted swiftly to Russian President Vladimir Putin declaring he would recognize the independence of two breakaway regions in eastern Ukraine, possibly using the move as a pretext for an invasion the U.S. has warned was likely coming at any hour.
The White House said Biden would soon issue an executive order "that will prohibit new investment, trade, and financing by U.S. persons to, from, or in" the two Ukrainian regions under the control of Russian-backed separatists, Donetsk and Luhansk.
The order "will also provide authority to impose sanctions on any person determined to operate in those areas of Ukraine," White House press secretary Jen Psaki said in a statement. She added that the U.S. "will also soon announce additional measures related to today’s blatant violation of Russia’s international commitments."
But the White House added these sanctions were not the same punishing ones the U.S. has threatened for weeks -- crippling Russia's banking sector, restricting access to semiconductors, targeting Putin and those close to him, and more -- if Russia actually launched an invasion.
"These measures," Psaki said, "are separate from and would be in addition to the swift and severe economic measures we have been preparing in coordination with allies and partners should Russia further invade Ukraine."
The European Union said it, too, would "react with sanctions against those involved in this illegal act" of recognizing the Ukrainian regions' independence, which are under the separatists' partial control.
The announcements came soon after Putin said during a televised address that he would recognize the regions' independence.
“I believe that it’s necessary to take a decision that has long been coming — to immediately recognize the independence and sovereignty of the Donesk’s People’s Republic and the Luhansk People’s Republic,” Putin said, using the names the separatists use for the regions.
Moscow already de facto controls the two self-declared republics, which make up only a portion of the Donetsk and Luhansk provinces, with the authorities answerable to Russian operatives.
Putin's announcement and subsequent decrees he signed recognizing the regions' independence -- expected to be ratified by Russia's parliament on Tuesday -- raised the question of whether he would then take the more provocative step of formally annexing them, and sending Russian troops into Ukraine.
The American sanctions were comparable to the actions the U.S. took after Russia invaded Ukraine's Crimean Peninsula in 2014, and most people impacted would already have likely been subject to sanctions anyway, according to Thomas Graham, who served as the White House National Security Council's director for Russia under George W. Bush.
"These aren't going to have much of an impact, if at all," on what Russia does moving forward, Graham, an expert on Russia at the Council on Foreign Relations, told ABC News.
During Putin's lengthy speech, Biden spoke on the phone for 35 minutes with Ukraine's President Volodymyr Zelenskyy, according to the White House.
Biden also spoke for half an hour today with German Chancellor Olaf Scholz and French President Emmanel Macron, according to the White House; both spoke with Putin over the past couple days.
Earlier, Vice President Kamala Harris, Defense Secretary Lloyd Austin, CIA Director William Burns, and the chairman of the Joint Chiefs of Staff, Gen. Mark Milley, all arrived at the White House for a meeting of Biden's national security team on Presidents Day morning
Previously, while the U.S. and Western allies have said they would be united in imposing severe sanctions on Russia if it invades Ukraine, they had been more ambiguous about what steps they would take if Russia stopped short of a full-on invasion. Secretary of State Antony Blinken said last week that Russia recognizing the regions' independence would "necessitate a swift and firm response from the United States in full coordination with our allies and partners."
The White House meeting came a day after officials said Biden was, "in principle," open to a summit with Putin, brokered by France's President Emmanuel Macron, on the condition that Russia did not invade. Russian officials were cool to the idea on Monday.
During their meeting with Putin, Russia's defense minister, foreign minister, chiefs of intelligence agencies, and the heads of parliament and senate, all called on Putin to recognize the independence of Donetsk and Luhansk.
Biden said Friday the U.S. had "reason to believe" that Russia would invade "within days." On Sunday, U.S. officials told ABC News that lower-level Russian tactical commanders had been making plans on the ground, at the local level, to invade Ukraine.
A senior Biden administration official said Sunday that no plans existed yet for a potential Biden-Putin summit, and that Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov would discuss the format and timing later this week – as long as Russia did not invade.
The diplomatic proposal emerged from two calls Macron held with Putin and one with Biden Sunday; his second with Putin began around 1 a.m. Moscow time Monday morning, according to the Elysée Palace.
Biden told Macron that, "in principle, he would be prepared to meet with Putin if President Putin stood down from his invasion," Biden's top national security adviser, Jake Sullivan, said in an interview with "Good Morning America" on Monday.
But, Sullivan added, "We can't say anything other than indications on the ground look like Russia is still moving forward."
Meanwhile, during their meeting in Moscow, Putin and top Russian national security officials bluntly questioned the usefulness of holding any new summit with Biden, suggesting it would be pointless unless the United States had changed its position.
Putin said that Macron suggested there were some "changes" in the U.S. position, although he added he could not see what they would be. Russia's foreign minister said he would speak to his French counterpart today – but was sure the U.S. would not provide positive responses to Russia's needs.
Even as U.S. officials warned a Russian invasion appears imminent, they also said they were still open to talking.
"We never give up hope on diplomacy until the missiles fly or the tanks roll," Sullivan said. "We've been working hard for months with our allies and partners to get Russia to sit down in a serious way at the table."
But, he added, "The likelihood there's a diplomatic solution, given the troop movements of the Russians, is diminishing hour by hour."
ABC News' Cecilia Vega, Mary Bruce, Sarah Kolinovsky, Luis Martinez, Conor Finnegan and Patrick Reevell contributed to this report.