Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty

The Pentagon announced a new $400 million defense package for Ukraine on Thursday.

The new aid will include four short-range Avenger air defense systems, which is a first for the packages approved for the war in Ukraine. It will also include more missiles for HAWK air defense systems, more anti-aircraft Stinger missiles, HIMARS ammunition, precision-guided artillery rounds and Humvees.

The Ukrainians will need some training on the Avengers, according to Deputy Pentagon press secretary Sabrina Singh, who did not give an estimate on when the systems might arrive and be ready to use.

With this latest drawdown, the U.S. has now committed more than $18.6 billion for the war since Russia invaded Ukraine on Feb. 24.

-ABC News' Matt Seyler

A new U.S. assessment estimates 100,000 Russians have been killed or wounded in the war in Ukraine, according to Gen. Mark Milley, the chairman of the Joint Chiefs of Staff.

The U.S. last gave an estimate in early August that the number of Russians killed and wounded was between 70,000 and 80,000.

"There has been a tremendous amount of suffering, human suffering, you're looking at maybe 15, 20, 30 million refugees, probably 40,000 Ukrainian innocent people who are civilians have been killed as collateral damage," said Milley.

He added, "You’re looking at well over 100,000 Russian soldiers killed or wounded, same thing probably on the Ukrainian side."

He pointed out that Russia invaded Ukraine with a force of 170,000 troops.

-ABC News' Luis Martinez

Russian oligarch Yevgeny Prigozhin, who runs the private military company Wagner, said Wednesday that Russia’s retreat from the key Ukrainian city of Kherson was painful but necessary.

Prigozhin, nicknamed "Putin's Chef" due to his restaurant and catering businesses, said Russian troops had to withdraw from Kherson because they were nearly surrounded by Ukrainian forces and cut off from supply lines.

“Neither I, nor Wagner abandoned Kherson," Pigozhin said. "Without question, it is not a victorious step in this war, but it’s important not to agonize, nor to fall into paranoia, but to make conclusions and work on mistakes."

He praised Russian Gen. Sergey Surovikin for making the decision to withdraw Russian troops and saving the lives of thousands of soldiers.

-ABC News' Patrick Reevell

Russia’s defense minister and top commander in Ukraine announced Wednesday that Russian troops will pull back from the key city of Kherson in southern Ukraine.

Defense minister Sergey Shoigu said he accepted a proposal from Russian Gen. Sergey Surovikin to order Russian forces to retreat to the eastern bank of the Dnieper River, in effect abandoning the city of Kherson.

Surovikin said it was a “very difficult decision” and justified it as necessary to save the lives of Russian soldiers and to preserve their capacity for future operations.

“Besides that, it frees up part of the forces and resources, which will be employed for active actions, including offensive, in other directions,” Surovikin said in the televised meeting with Shoigu.

Kherson is the only regional capital the Russians have occupied since 2014. The city and the surrounding area act as a gateway to Crimea Peninsula, which was annexed by Russia in 2014.