Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

Russia has launched another wave of missile strikes on energy infrastructure sites across Ukraine, resulting in severe power outages in large parts of the country.

There have been least three explosions in Kyiv by early Friday morning while other cities, including Kryvi Rih, Kharkiv, Dnipro and Zaporizhe, have also been targeted this morning, ABC News has learned.

According to officials in Kryvi Rih, a residential building has been hit. Details on possible casualties are still emerging.

Officials in Kharkiv say there have been at least three explosions there and reports suggest Ukraine’s second city is completely without power.

There are shortages of running water in Kyiv right now and a large part of the city is without power.

Initial information suggests Russia has fired dozens of missiles and Ukraine’s air defenses have been operating. It's likely many missiles have been shot down but some have clearly found their targets.

It's currently unclear if Russia used drones in the waves of strikes this morning.

Russia's foreign ministry spokesperson offered an angry response to reports that the United States is preparing to send Patriot air defense missiles to Ukraine.

During a news conference Thursday, Maria Zakharova said that if media leaks are true, the move by the White House "would be another provocative step."

"Given the increasing amounts of direct U.S. military assistance, including the presence of U.S. servicemen on the ground, the delivery of equipment of such complexity, the operation of which requires months of training, will signify a broader involvement of U.S. career servicemen in the hostilities with all the ensuing consequences," Zakharova said.

Two U.S. officials have confirmed to ABC News that the United States has prepared plans to send Patriot air defense missile systems to Ukraine that could be approved by President Joe Biden by the end of this week.

If approved by Biden, the transfer of the advanced air defense systems would meet a long-standing request from Ukraine.

"We strongly recommend that the decision-makers in Washington finally listen [...] and draw the right conclusions from our repeated warnings that any weapon systems delivered to Ukraine, including Patriot, and the respective personnel, have been and remain legitimate priority targets of the Russian Armed Forces," Zakharova said.

Ukraine's defense minister is claiming in a news interview that Russian President Vladimir Putin is planning a major new offensive to launch in the new year.

Oleksii Reznikov told the British newspaper The Guardian that emerging evidence indicates the Kremlin is preparing a broad new offensive possibly in February.

Reznikov said the new offensive is part of a second wave of a mobilization of 300,000 reservists Putin announced in September.

"The second part of the mobilization, 150,000 approximately, started their training courses in different camps," Reznikov said. "The [draftees] do a minimum of three months to prepare. It means they are trying to start the next wave of the offensive probably in February, like last year. That’s their plan."

News of the possible offensive comes after a series of setbacks the Russians have had on the battlefield, including a botched attempt in March to the take Kyiv, the Ukrainian capital.

A U.S. Air Force veteran from Minnesota was freed Wednesday from Russian-controlled territory and told ABC News he survived being beaten and electrocuted by his captors.

Suedi Murekezi, 35, was freed in a war gray zone just outside Zaporizhzhia in southern Ukraine. A prearranged two-hour cease-fire was called to allow an exchange of prisoners of war.

Murekezi and other prisoners of war were brought out of Russian-controlled territory as part of the exchange. Following his release, Murekezi was seen clutching a Ukrainian flag given to him by a Ukrainian military intelligence officer.

Murekezi was arrested in June when he was falsely accused by the Russians of being a member of the CIA, he said. He said he was later released; however, he was stuck in Donetsk, a city in Russian-controlled territory, because he was without his U.S. passport.

In an exclusive interview with ABC News, Murekezi said he felt "trapped" in Donetsk and lived under intense uncertainty about his future.

He said he was relieved and happy to be back in Ukrainian-controlled territory, a free man in the country where he has lived for years, working in cryptocurrency.

What he is looking forward to most when he gets back to Minnesota? "A peanut butter sandwich," Murekezi said.

-ABC News' Tom Soufi Burridge, Dada Jovanovic, Natalia Kushniir and Kuba Kaminski