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

Soviet-era tanks are getting new optics, armor, and more at a Czech facility in Šternberk, thanks partly to the efforts of Ukrainian refugees working there.

Around 150 people have been hired by Excalibur Army in an effort to modernize old military equipment from around the world, which will then be shipped to Ukraine after months of work on upgrades.

According to the company's commercial director, Richard Kuběna, it is concentrating on a large order to modernize up to 120 T-72 tanks, which the U.S. and the Netherlands governments ordered and paid 2.2 billion crowns for.

The tanks were ordered initially from Šternberk by an African country. However, after negotiating with the U.S., E.U., and Czech Ministry of Defense, they decided to give the tanks to Ukraine, Kuběna said.

"Next week, the first five units of tanks for Ukraine will be received, we would like to deliver 18 units by the end of the year," noted Kuběna.

Kuběna said he would like to deliver a total of 90 tanks to Ukraine.

-ABC News’ William Gretsky

Ukraine’s Prime Minister Denys Shmyhal has agreed to allow the International Atomic Energy Agency, a United Nations watchdog group, to dispatch nonstop safety and security teams to all of the nuclear plants in the country.

The move is part of efforts to prevent a nuclear incident during the country’s war with Russia, the IAEA said in a statement on Tuesday.

Over the past month, Ukraine and the IAEA have conducted week-long nuclear safety missions at three in-use nuclear plants in the country, as well as Chernobyl. Tuesday’s decision makes their effort permanent.

“This is especially important at a time when Ukraine’s energy infrastructure is facing unprecedented challenges as a result of the war and in the middle of the winter,” IAEA Director General Rafael Mariano Grossi said in a statement.

A Kremlin official said on Tuesday that Russia’s withdrawal from Ukraine was “out of the question.”

A reporter asked Kremlin spokesman Dmitry Peskov for comment on Ukrainian President Volodymyr Zelenskyy’s proposal that Russia start to pull out forces from Ukraine before Christmas. Peskov was also asked whether Moscow was ready to do so before the end of this year.

“This is out of the question,” Peskov said.

-ABC News’ Joe Simonetti and Anastasia Bagaeva

President Joe Biden spoke with Ukrainian President Volodymyr Zelenskyy on Sunday to discuss continued support for Ukraine's defense amid Russian attacks on critical infrastructure, according to a White House readout of their call.

"President Biden highlighted how the U.S. is prioritizing efforts to strengthen Ukraine's air defense through our security assistance, including the December 9 announcement of $275 million in additional ammunition and equipment that included systems to counter the Russian use of unmanned aerial vehicles," the White House said.

"President Biden also highlighted the November 29 announcement of $53 million to support energy infrastructure to strengthen the stability of Ukraine's energy grid in the wake of Russia's targeted attacks," it added.

-ABC News' Justin Ryan Gomez