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

Former President Barack Obama released a statement Thursday afternoon condemning Russia's invasion of Ukraine.  

Obama warned that the invasion threatened "the foundation of the international order and security."

"For some time now, we have seen the forces of division and authoritarianism make headway around the world, mounting an assault on the ideals of democracy, rule of law, equality, individual liberty, freedom of expression and worship, and self-determination. Russia’s invasion of Ukraine shows where these dangerous trends can lead – and why they cannot be left unchallenged," he said.

Obama called on Americans and other world leaders to support the Ukrainian people and President Joe Biden's sanctions on Russia.

"For over the long term, we all face a choice, between a world in which might makes right and autocrats are free to impose their will through force, or a world in which free people everywhere have the power to determine their own future," Obama said.

The U.S. believes Russia has launched more than 160 missiles, mostly short-range ballistic missiles, but some medium-range and cruise missiles, as well, a senior defense official told reporters.

The official said the U.S. believes Russian troops have gotten closer to Kyiv.

"We also have seen indications since we last talked of additional airborne troops into Kharkiv" in northeast Ukraine, the official said in a briefing. "And our assessment is still that there's active fighting going on there."

-ABC News' Matt Seyler

President Joe Biden will participate in a NATO conference virtually from the Situation Room beginning at 9 a.m. ET Friday, a White House official confirmed.

NATO Secretary General Jens Stoltenberg will offer public opening remarks and a press conference after the meeting.

Russian troops have reportedly taken full control of the area around the Chernobyl nuclear power station, including the plant itself, according to Ukraine’s prime minister.

“Unfortunately, we are obliged to inform that as things stand the Chernobyl Zone, the so-called ‘Exclusion Zone’ and all the Chernobyl nuclear power station have been taken under the control of the Russian armed groups,” prime minister Denis Schmygal told UNIAN, Ukraine’s main news wire.

A senior defense official said they couldn't confirm reports that Russian troops seized control. "We do believe with some confidence that some Russian soldiers have moved through that area and may still be in that area, but we can't confirm ... that they've taken control," the official said.

The Chernobyl power plant, the site of the world's worst nuclear accident, is located about 60 miles north of the Ukrainian capital, Kyiv. The Chernobyl exclusion zone begins almost immediately below Ukraine's border with Belarus.

The nuclear facilities at Chernobyl are "operating safely and securely," Ukraine's regulatory body informed the United Nations nuclear watchdog.

The International Atomic Energy Agency expressed alarm at the fighting around Chernobyl, but in a note to the IAEA, Ukraine confirmed that "unidentified armed forces" have taken control of all facilities, and that there were no casualties or destruction at the industrial site, the IAEA said.

Still, any attack on nuclear facilities is considered a "violation of the principles of the United Nations Charter, international law, and the Statue of the Agency," the IAEA's members agreed in 2009.

-ABC News' Patrick Reevell, Conor Finnegan