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

Russian forces have withdrawn their troops from the once-occupied Ukrainian city of Lyman as Ukraine's eastern counteroffensive recaptures more territory, Russia's Tass and RIA news agencies said Saturday citing the Russian defense ministry.

Lyman is 100 miles southeast of Kharkiv, Ukraine's second-largest city. Ukrainian forces had pushed across the Oskil River as part of a successful counteroffensive that allowed it to reclaim occupied territories beginning in September.

Lyman, a key transportation hub, had been an important site in the Russian front line for ground communications and logistics. Now that Ukraine has reclaimed the territory, it can push further, potentially into the occupied Luhansk region, one of the four areas Russia annexed Friday.

In a statement, the Russian Defense Ministry said it withdrew its forces due to the risk of being encircled after the Ukrainians sent reserve forces and continued the offensive.

-ABC News' Somayeh Malekian

Russian forces are accused of shelling a convoy of seven civilian cars killing 22 people, including 10 children, according to preliminary data, Olexandr Filchakov, chief prosecutor of the Kharkiv region, told ABC News.

According to preliminary data, the cars were shot by the Russian military on Sept. 25, when civilians were trying to evacuate from Kupyansk, a settlement in the Kupyansk area, Filchakov said.

The column of shot cars was discovered on Friday. Two cars burned completely with children and parents inside, Filchakov said.

Filchakov said the bodies burned completely.

Russian forces fired at the column with a 12.5 mm caliber gun. Those who remained alive were then shot at with rifles, according to Filchakov.

-ABC News' Somayeh Malekian

The White House reiterated its warning Friday that there is a risk Russia may consider the use of nuclear weapons, but there are no indications of an "imminent use of nuclear weapons."

"I've been clear myself, President Biden has been clear, the administration has been clear that there is a risk given all of the loose talk and the nuclear saber rattling by Putin, that he would consider this and we've been equally clear about what the consequences would be," National Security Advisor Jake Sullivan said.

Asked if the threat was higher now than it was at the start of the invasion of Ukraine, Sullivan wouldn't characterize a risk level, but noted that "the risk has been there from the start."

Sullivan added, "What's interesting is that at various points over the course of this conflict, including right at the outset, Putin has brandished the nuclear card. He's doing it again."

Asked by ABC's Terry Moran about Vladimir Putin's speech Friday, accusing the U.S. and the West of values equal to "Satanism" and attacking "liberal values," Sullivan said, "its raving."

-ABC News' Terry Moran and Justin R. Gomez

After President Joe Biden said that the Nord Stream pipeline leaks were a "deliberate act of sabotage," the White House made clear the U.S. isn't yet attributing who is behind those attacks, but told ABC's Terry Moran that they "do not believe that this was the work of any NATO ally."

National Security Advisor Jake Sullivan was careful not to directly blame Russia, though he didn't rule out the possibility they were behind it given their response to the attacks.

"Russia has done what it frequently does when it is responsible for something, which is make accusations that it was really someone else who did it," Sullivan said.

Sullivan said the U.S. can "unequivocally" say that the "suggestions Russia has made about the United States and other countries are flat out false."

When asked how many other countries have the capabilities to even carry out this kind of attack, Sullivan said, "not many."

Asked if the White House is concerned that there could be an attack on U.S. and Western infrastructure after the Nord Stream incident, he said "we have been concerned about that from the beginning of the war," but didn't have specific intelligence to share on current threats.

-ABC News' Terry Moran and Justin R. Gomez