Russia-Ukraine updates: Putin says 'certain positive movements' in negotiations

At least some of the losses the Russians acknowledged Wednesday were due to weapons the U.S. provided Ukraine, acting U.S. Ambassador to Ukraine Kristina Kvien told ABC News.

The U.S. has supplied defensive weapons to Ukrainians including anti-tank Javelins and anti-aircraft Stingers, along with ammunition and other supplies.

"We don't know which individual piece of hardware did which individual thing, but let's just say my understanding is Javelins have been extremely effective against Russian onslaught," Kvien said.

"When you see on television some of these Russian tanks or planes blowing up that's partly due to the weapons we have been able to provide," she added.

Kvien told ABC News the U.S. would continue to push weapons and ammunition into the hands of the Ukrainians, but declined to discuss how they are getting into the country. 

-ABC News' Aaron Katersky

The White House announced it will impose several new sanctions and restrictions on Russia and Belarus on Wednesday. 

The U.S. will be placing export controls on extraction equipment and refining technology needed for Russia's oil and gas industry.  

The White House argues this will degrade Russia's oil and gas industry over time, as it will prevent them from maintaining and upgrading current projects and, to some degree, future projects and likely make Russia a less desirable place for foreign oil and gas companies to invest in. 

The U.S. will also impose full-blocking financial sanctions, its toughest sanctions, on 22 entities that support Russia's defense sector. These entities make combat aircraft, infantry fighting vehicles, electronic warfare systems, missiles, and unmanned aerial vehicles for Russia’s military, according to the White House.

Export controls currently placed by the U.S. on Russia will be extended to Belarus, cutting them off from access to semiconductors and other technology. The U.S. will also sanction entities that support Belarus's military. 

-ABC News' Ben Gittleson

Russian oligarch Roman Abramovich confirmed on Wednesday that he will sell the Chelsea soccer club. 

Abramovich said he instructed his team to set up a charity for the victims of the war in Ukraine where all net proceeds from the sale will be donated. 

"The foundation will be for the benefit of all victims of the war in Ukraine. This includes providing critical funds towards the urgent and immediate needs of victims, as well as supporting the long-term work of recovery," Abramovich said in a statement.

Abramovich said the sale of the club will not be fast-tracked. 

"This has never been about business nor money for me, but about pure passion for the game and Club," Abramovich said. "This has been an incredibly difficult decision to make, and it pains me to part with the Club in this manner. However, I do believe this is in the best interest of the Club."

-ABC News' Zoe Magee

The UN refugee agency, UNHCR, said on Wednesday that 874,026 people have fled Ukraine, more than half of which have fled to Poland, according to its count.

According to the UNHCR, 453,982 Ukrainians have fled to Poland, 116,348 people to Hungry and 79,315 to Moldova. The agency said 69,600 people have fled to other European nations.