Russia is concerned by U.S. President Joe Biden's recent remark seemingly regarding the need for a change of administration in Moscow, Kremlin spokesman Dmitry Peskov said Monday.

In an address on Saturday from Poland's capital, Warsaw, Biden made a comment that appeared to be directed at Russian President Vladimir Putin and his invasion of Ukraine.

"For god's sake, this man cannot remain in power," Biden said.

After the speech, the White House released a statement clarifying that Biden wasn't calling for a regime change.

"The President's point was that Putin cannot be allowed to exercise power over his neighbors or the region. He was not discussing Putin’s power in Russia, or regime change," a White House official said.

When asked by reporters on Monday about Biden's remark, Peskov replied: "Indeed, this statement makes us worry."

"We will continue to closely monitor statements made by the U.S. president," he added. "We are thoroughly recording them and will be continuing to do so."

The cost of direct damage to Ukraine's infrastructure amid Russia's ongoing invasion has already reached almost an estimated $63 billion, according to an analysis by the Kyiv School of Economics.

As of March 24, at least 4,431 residential buildings, 92 factories and warehouses, 378 institutions of secondary and higher education, 138 health care institutions, 12 airports, seven thermal power plants and hydroelectric power plants have been damaged, destroyed or seized in Ukraine since the start of the Russian invasion on Feb. 24, according to the Kyiv School of Economics.

Meanwhile, Ukraine's overall economic losses due to the war range from $543 billion to $600 billion, the Kyiv School of Economics said.

The Russian Ministry of Justice on Monday added German broadcaster Deutsche Welle (DW) to a list of media organizations it has labeled as "foreign agents."

The justice ministry said in a statement that it made the decision "based on the documents received from the authorized state authorities," without providing further details. The designation requires media outlets to publish a disclaimer on all its publications.

"This latest, arbitrary decision by the Russian authorities was unfortunately to be expected," DW director Peter Limbourg said in a statement. "It is a further attack on press freedom and a fresh attempt to cut the Russian population off from free, independent media."

"It started with the forced closure of our studio in Moscow at the beginning of February, then our website in all languages was blocked in Russia. There then followed the gradual restriction of social media services and now DW has been labeled a 'foreign agent,'" he added. "This will not stop us from continuing to provide comprehensive and independent coverage of Russia and the region from our new studio in Latvia and from Germany. We will have to put a lot more effort into censorship circumvention tools in the future. This includes VPN clients like Psiphon or the Tor browser, which we already use."

Russian independent newspaper Novaya Gazeta, whose editor was a co-winner of last year's Nobel Peace Prize, announced Monday that it is suspending publication until the war ends in neighboring Ukraine.

Novaya Gazeta was the last remaining established independent media outlet still operating in Russia and trying to cover the invasion of Ukraine, despite strict censorship. Its decision to halt operations is another watershed moment in the silencing of free media across Russia.

The Moscow-based paper, famous for its critical and investigative coverage of Russian President Vladimir Putin's regime, said it made the decision after receiving a second warning from Russia's state communications and media watchdog, Roskomnadzor, for allegedly violating the country's repressive "foreign agent" law. Another alleged violation could allow a court to shut Novaya Gazeta down completely.

Novaya Gazeta is best-known by Western countries for the fact that six of its journalists have been murdered since 2000, including most famously Anna Politkovskaya. Last October, the paper's editor-in-chief, Dmitry Muratov, was jointly awarded the 2021 Nobel Peace Prize with Maria Rosa, one of the Philippines' most prominent journalists, for "their efforts to safeguard freedom of expression, which is a precondition for democracy and lasting peace."

Before Russian forces attacked Ukraine on Feb. 24, there was still a very small number of popular, influential media outlets able to operate in Russia -- albeit under permanent pressure from the government. But since the war began, austerities have moved to crush all of them, and dozens -- likely hundreds -- of independent journalists have fled abroad. Most are now publishing articles from outside the country. Novaya Gazeta is arguably the most symbolic closure. The paper was co-founded in 1993 by former Soviet leader Mikhail Gorbachev, who still sits on its board.

Novaya Gazeta said in a statement Monday that it is suspending publication until the end of Russia's so-called "special military operation in Ukraine," the term the Russian government is using instead of war or invasion. Russia has banned media from using those words to describe the situation. But Novaya Gazeta had been getting around that ban with some symbolic gestures, including blank pages, and replacing the word "war" in its articles with phrases like "word forbidden by Russian government."

-ABC News' Patrick Reevell

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