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

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

A senior U.S. official met with a Russian delegation in Istanbul on Friday to discuss "a narrow set of bilateral issues," according to a spokesperson from the State Department.

Citing a hesitancy to discuss "private diplomatic discussions," the spokesperson declined to provide additional detail, but other sources say the agenda was focused on embassy staffing levels, visas, and related matters.

A spokesperson added that the war in Ukraine was not discussed, nor was Paul Whelan’s case.

The meeting was initially reported by Russian News Agency TASS.

-ABC News' Shannon Crawford