Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

NATO Secretary-General Jens Stoltenberg told reporters Wednesday that he expects allies to announce major increases to forces in the eastern part of the defense alliance at Thursday's summit.

Stoltenberg said the first step would be the deployment of four new NATO battle groups in Bulgaria, Hungary, Romania and Slovakia. With the existing forces in place, there will be eight multi-national battle groups all along the eastern flank, from the Baltic to the Black Sea.

"We face a new reality for our security, so we must reset our deterrence and defense for the longer term," Stoltenberg said.

Stoltenberg said he expects allies will agree to provide additional support to Ukraine, including cybersecurity assistance and equipment to help Ukraine protect against chemical, biological, radiological and nuclear threats.

He added that NATO has a responsibility to make sure the conflict does not escalate beyond Ukraine, as "this will cause even more death and even more destruction."

Stoltenberg also called on Belarus to end its complicity in the war.

-ABC News' Christine Theodorou

The first deliveries from the $800 million military assistance that U.S. President Joe Biden authorized for Ukraine a week ago have started to arrive, a White House official told ABC News on Wednesday.

The military aid package includes Stinger anti-aircraft systems, Javelin anti-armor weapons, light anti-armor weapons, AT-4 anti-armor systems and tactical unmanned aerial systems.

CNN was first to report the deliveries.

-ABC News' Justin Gomez

The governor of Ukraine's Chernihiv Oblast, Viacheslav Chaus, claimed Wednesday that Russian forces have destroyed the bridge linking the region to the Ukrainian capital, Kyiv.

In a video posted on Telegram, Chaus shows the destroyed bridge over the Desna river, which he said effectively means that the road from Chernihiv to Kyiv is now severed.

-ABC News' Fergal Gallagher

Russia and Ukraine have agreed on nine humanitarian corridors to try to evacuate civilians trapped in embattled Ukrainian towns and cities on Wednesday, according to Ukrainian Deputy Prime Minister Iryna Vereshchuk.

But the agreement does not include a safe passage from the heart of Mariupol, Vereshchuk said in an address Wednesday, adding that she hopes people wishing to leave the besieged southeastern port city can make it to nearby Berdyansk, where humanitarian aid awaits them. She said 24 buses are on standby to transport people.

Some of the previous attempts to evacuate civilians from Mariupol have failed after Russian forces continued to shell the city, despite agreeing to temporary cease-fires.