A Moscow court has ruled that the use of Instagram and Facebook are to be banned effective immediately under Russia's anti-extremist legislation, Russian state-run news agency TASS reported on Monday.

The court banned the operations of Meta, the company that owns Facebook and Instagram, “on the grounds of realizing extremist activity,” Judge Olga Solopova announced Monday in a Moscow court.

The ban does not apply to WhatsApp, the messenger app also owned by Meta, “as it has no option to publicly spread information,” Solopova said.

-ABC News' Christine Theodorou

The U.S. Department of State has not yet confirmed reports that Russia is forcibly moving Ukrainian civilians to Russia but is investigating the claims, State Department spokesperson Ned Price said Monday.

"We are in close consultation with our Ukrainian partners, with others who may be able to provide firsthand accounts of what is taking place on the ground," Price told reporters at a briefing. "Of course, these reports are deeply concerning, and if true, they would be -- amount to additional evidence of what would appear -- to be the mistreatment of civilians."

Beyond that, Price said the U.S. is seeing "evidence everyday pointing to acts, actions, activities that may constitute war crimes."

"We continue to call on the Russian government to allow genuine safe passage so that civilians can depart cities and towns in Ukraine that are besieged by Russian forces and allow deliveries of humanitarian goods," Price said. "The reality continues to be that while humanitarian goods are gathered and en route to the areas most in need, the convoys typically are not able to reach people in besieged cities."

On Monday, Mikhail Mizintsev, head of the Russian National Defense Control Center, claimed that about 347,000 Ukrainians have evacuated "from dangerous areas of Ukraine and the Luhansk and Donetsk People's Republics" into Russia.

-ABC News' Conor Finnegan

Pro-Kremlin newspaper Komsomolskaya Pravda reported that nearly 10,000 Russian troops have died as a result of the invasion into Ukraine.

The newspaper published an article Monday that included a paragraph stating that Russia’s defense ministry said its losses in Ukraine are 9,862 dead and 16,153 injured.

"Russia’s Ministry of Defense denies the information of the Ukrainian General Staff about alleged large-scale casualties among the Russian Armed Forces in Ukraine," the article stated. "According to the data of the Russian ministry of defense, in the course of the special operation in Ukraine, Russia’s armed forces have lost 9,861 dead, 16,153 have received wounds."

Not long after journalists online spotted the number, the article vanished and then was reposted without any mention of Russian casualties, indicating that the newspaper likely published the figure unwittingly.

If a journalist deliberately posted the death toll, they could be severely prosecuted under a new Russian law.

Komsomolskaya Pravda later claimed in a statement that it was hacked and that a "fake" was added to one of its articles.

"On March 21, website admin interface was hacked and a fake was added to a publication about the situation around the special operation in Ukraine," the statement read.

Russia has not published an official death toll for its forces since March 3, when it said just 498 of its troops had been killed.

The U.S. has estimated that between 2,000 and 10,000 Russians have been killed in the conflict.

Mikhail Mizintsev, head of the Russian National Defense Control Center, claimed that about 347,000 Ukrainians have evacuated to Russia.

The evacuations occurred "without the participation of the Kyiv authorities," Mizintsev alleged during a press conference Monday, claiming that officials in Kyiv "again have not approved any of the four humanitarian corridors in Russia's direction proposed by the Russian side."

Mizintsev also alleged that Kyiv refuses to conduct humanitarian operations in the besieged city of Mariupol by withdrawing Ukrainian forces from the city.

"At 2 a.m. on March 21, 2022, we received an unsubstantiated refusal to rescue people, and a surrender and laying down arms are out of the question," Mizintsev said, adding that more than 130,000 people remain blockaded in the city.

Mizintsev claimed that in the past 24 hours alone, 16,054 people, including 4,631 children, were evacuated "from dangerous areas of Ukraine and the Luhansk and Donetsk People's Republics" into Russia.

Moscow had had offered safe passage out of Mariupol in return for the city's surrender before 4 a.m. Monday, but Ukraine rejected the offer well before the deadline.

All Russian troops have left the Ukrainian cities of Kyiv and Chernihiv, withdrawing north toward the borders of Belarus and Russia to consolidate before likely redeploying to the Donbas region in eastern Ukraine, a senior U.S. defense official told reporters Wednesday.

But even with the Russians gone, the territory remains treacherous.

"There are some indications that they left behind mines and things like that, so the Ukrainians are being somewhat careful in some areas north of Kyiv as they begin to clear the ground and clear the territory and re-occupy it," the official said.

While the U.S. hasn't yet seen these troops redeploy elsewhere in Ukraine, it'll likely happen soon, according to the official. Ukrainian forces are preparing for a major fight in Donbas, the official said.

The official also said the Pentagon is "monitoring" an apparent nitric acid explosion in Ukraine's Luhansk region, which Russia blamed on Ukraine.

"We've seen the Russians claim that this was a Ukrainian attack on this. We do not believe that is true," the official said. "We do believe that the Russians are responsible, but exactly what they used when they did it, why they did it, what the damage is, we just don't have that level of detail," the official said.

The official also noted that a small number of Ukrainians currently in the U.S. for "professional military education" were pulled aside for a couple days of training on Switchblade drones, which the U.S. is sending overseas as part of its military aid, according to the official.

"Although it's not a very difficult system to operate, we took advantage of having them in the country to give them some rudimentary training on that," the official said.

-ABC News' Matt Seyler