Russia-Ukraine updates: US to ban Russian carriers from its airspace

Russian President Vladimir Putin has no plans to call off his invasion of Ukraine, a U.S. official warned ABC News Thursday.

"He is not going to stop," the official said, adding that Putin believes he has the firepower to stop any insurgency. "He is like a madman. ... He wants to take the whole country."

The official also warned that the Ukrainian army is no match for Russia's vast forces.

"Ukrainians don’t have strong air power. One airport looked like they fought back and then Russians paratroopers came in and wiped them out," they said.

The toppling of Kyiv could come quickly and Ukrainian President Volodymyr Zelenskyy may also be killed if he is found, the official said. The president said as much in a TV address, noting he was Russian enemy No. 1 and that his family had gone into hiding.

The official said once a full ground invasion begins there could be a massive refugee crisis, with Ukrainians looking to flee the country and only a few border crossings.

-ABC News' Martha Raddatz

U.S. President Joe Biden has repeatedly said he will not order American forces to engage with Russia in Ukraine, but U.S. Secretary of State Antony Blinken reemphasized America's commitment to NATO's Article 5 during an interview with ABC News' David Muir on Thursday night.

"Is it a possibility that Putin goes beyond Ukraine? Sure, it's a possibility, but there's something very powerful standing in the way of that -- that's something we call Article 5 of NATO," Blinken said. "That means an attack on one member of NATO is an attack on all members of NATO. The president's been very clear that we will defend every inch of NATO territory."

Ukraine is not a member of NATO, though their push for inclusion is one of the main factors that motivated Russian President Vladimir Putin's invasion, but several other countries in the region are NATO members. The Baltic states -- Lithuania, Estonia and Latvia -- joined NATO in 2004, and are fearful of Putin's land grabs.

"It's been very clear that we are committed Article 5, we’re committed to defending our NATO allies, and if it comes to that, we'll do it," Blinken said. "But right now, our focus is on Ukraine, our focus is on trying to prevent President Putin from going even further. But it looks like he's going for everything he can get."

Homeland Security to take lead response to Russia-related impacts in US

The Department of Homeland Security has been tasked "to coordinate domestic preparedness and response efforts related to the current Russia-Ukraine crisis," the agency announced Thursday evening.

The agency said there are no current threats to the U.S. 

Homeland Security said it established a unified group "preparing for and responding to possible threats to the homeland; develop and pursue strategic objectives and priorities; and coordinate with federal, state, local, tribal, and territorial officials, as well as representatives of the private sector and nongovernmental entities in support of these objectives and priorities."

-ABC News' Luke Barr

Ukrainian President Volodymyr Zelenskyy provided a televised update on the Russian invasion and said his family is in hiding due to threats on their lives.

"The enemy has identified me as target No. 1 and my family as target No. 2. They want to destroy Ukraine politically by destroying the head of state," the president said.

Zelenskyy said he is staying in the government quarter "with everyone who is needed for the work of the central government." He reiterated that he and his family are not "traitors."

The president warned residents that "enemy sabotage groups have entered Kyiv."

"I am asking the residents very much: be careful, [and] follow the rules of the curfew," he said.

Zelenskyy said as of Thursday evening at least 137 people had been killed during the invasion, including 10 officers and 13 border guards.

Additionally, the president said at least 316 people have been wounded so far during the attacks.

-ABC News' Patrick Reevell, Christine Theodorou and Kirit Radia