Biden will announce the news in his State of the Union address, a source said.
Russian forces are continuing their attempted push through Ukraine from multiple directions, while Ukrainians, led by President Volodymr Zelenskyy, are putting up "stiff resistance," according to U.S. officials.
The attack began Feb. 24 as Russian President Vladimir Putin announced a "special military operation."
Russians moving from Belarus towards Ukraine's capital, Kyiv, don't appear to have advanced closer towards the city since coming within about 20 miles, although smaller advanced groups have been fighting gun battles with Ukrainian forces inside the capital since at least Friday.
Russia has been met by sanctions from the U.S., Canada and countries throughout Europe, targeting Russia's economy and Putin himself.
About 368,000 people have fled Ukraine into neighboring countries, as the number of refugees "continues to rise," the U.N. Refugee Agency said on Sunday.
The agency said earlier on Sunday that about 200,000 people crossed Ukraine’s borders as refugees. On Saturday, the figure had been about 150,000 people, said Filippo Grandi, U.N. high commissioner for refugees.
An intense battle is being waged on Sunday for Ukraine’s second largest city, Kharkiv, with Russia overnight pounding the city with rocket barrages and videos on Sunday showing street fighting.
Authorities said some columns of Russian light armored vehicles managed to enter the city and urged residents to stay indoors.
Video published in Ukrainian media and shared by an advisor to Ukraine’s interior minister, showed Ukrainian troops firing assault rifles and rocket propelled grenades, close to what appeared to be a destroyed column of Russian vehicles. Other videos showed the Ukrainian troops, wearing yellow bands on their arms, inspecting the bullet-riddled Russian armored cars.
The mayor of Kharkiv has denied claims he is negotiating with the Russian forces, instead posting a photo of a group of heavily armed police posing with guns and promising to continue fighting.
People on the ground overnight described heavy artillery barrages, including from Russian ‘Grad' multiple rocket launchers.
The Russian Defense Ministry claimed on Sunday that over 450 Ukrainian service members from an anti-air unit had surrendered in the Kharkiv region. A defense ministry spokesman, Igor Konashenkov, told a briefing the troops from a Buk M-1 missile unit from Ukraine’s 302nd Air Defense Regiment had been taken prisoner.
ABC News was unable to independently verify the claim.
-ABC News’ Patrick Reevell, Anastasia Bagaeva and Tanya Stukalova
Ukrainian President Volodymyr Zelenskyy denied a Kremlin suggestion his government will hold talks with Russia in Belarus.
Zelenskyy in a televised address on Sunday said Ukraine was ready to hold talks to end the fighting but not in Belarus, which is directly involved in assisting Russia’s invasion of Ukraine.
“If from your territory there wasn’t aggressive action, we could talk in Minsk. Now we will talk, but not in Minsk. The platform can be other cities for a meeting,” he said.
Zelenskyy said Ukraine had proposed meeting in Warsaw, Budapest, Istanbul and Bratislava, Slovakia’s capital -- but it appeared Russia had still insisted on Belarus.
“Warsaw, Bratislava, Budapest, Istanbul, Baku -- all these we proposed to the Russian side. And yes any other city in a country from where rockets aren’t flying. Only that way can talks be fair. And can really end the war,” he said.
Russia launched its offensive on Kyiv from Belarus, which is ruled by the Kremlin’s client, authoritarian leader Alexander Lukashenko. Thousands of Russian troops have moved south over the border there, and aircraft and missiles are taking off from Belarus.
The Kremlin on Sunday said a Russian delegation would go to Belarus and wait in the southern city of Gomel, close to Ukraine’s border, “ready to start negotiations.”
Russia has been demanding in effect that Ukraine come to negotiate its surrender and concede to Moscow’s demands to declare “neutral status.”
-ABC News’ Patrick Reevell
The Kremlin has said a Russian delegation has travelled to Belarus to hold talks with Ukraine.
Spokesman Dmitry Peskov said on Sunday that an agreement had been reached on holding talks and that the Russian delegation would go to the southern city of Gomel, close to Ukraine, where it would “be ready to start” negotiations.
But Ukrainian officials have not confirmed they are ready to join the negotiations.
“In accordance with an agreement that has been reached, a Russian delegation, consisting of representatives of the foreign ministry, ministry of defense and other bodies, including the presidential administration, has arrived in Belarus for negotiations with the Ukrainians. We are ready to start these negotiations in Gomel,” Peskov told reporters.
On Friday, the Kremlin proposed talks in Belarus, saying Ukraine’s President Volodymyr Zelenskyy was ready to discuss his country’s “neutral status,” which would potentially mean abandoning its NATO ambitions. Zelenskyy has not confirmed that.
Zelenskyy's office said yesterday that Ukraine is ready to hold talks at anytime to stop the fighting, but has not spoken of concessions. His office has said it has been discussing a possible place and time to hold talks, stressing that those talks would not be between Zelenskyy and Russian President Vladimir Putin.
-ABC News’ Patrick Reevell
