The U.S. Department of Defense announced an additional $400 million aid package to Ukrainian forces that includes more weapons and ammunition.

This marks the Biden administration's 43rd military aid package to Ukraine since August 2021.

Some of the equipment and weapons in this package include, additional munitions for Patriot air defense systems and National Advanced Surface-to-Air Missile Systems (NASAMS); Stinger anti-aircraft systems and Javelin and other anti-armor systems and rockets.

-ABC News' Matthew Seyler

Ukraine has begun using the controversial cluster munitions that the U.S. recently began providing to Ukraine, a U.S. official confirmed to ABC News.

Ukraine, Russia and the U.S. are not signatories to the convention that bans the use of cluster munitions. Russia has used them in the war in Ukraine and so has Ukraine as they a supply of the weapons left over from the Soviet era.

"I believe they have started using them," Pentagon deputy press secretary Sabrina Singh said Thursday. "In terms of the effect on the battlefield, I'd really let Ukraine speak to how they intend to employ them. But you know, this is a powerful artillery that we have given them. They have ... committed to use it responsibly, to keep track and record where they are using it, so when this war is over, they can begin those de-mining efforts."

The weapons are considered dangerous to civilians because the small bomblets that are dispersed by the munitions can remain unexploded until someone accidentally stumbles upon them weeks, months or even years later.

-ABC News' Luis Martinez

Russian forces hit a three-story building and a garage in the city center of Mykolaiv Thursday morning, local time, injuring nine people, including five children, the Mykolaiv Regional State Administration said on Telegram.

There were fatalities stemming from the strikes, but it's unclear how many at this time, the Mykolaiv Regional State Administration added.

In another incident, Russian strikes hit Odesa early Thursday morning, the Odesa District Administration said on Telegram.

Two people were injured and hospitalized from the attack, according to the Odesa District Administration.

There is destruction "in the center" of Odesa and a fire broke out stemming from the strikes, the administration said.

-ABC News' Natalia Kushniir and Yuriy Zaliznyak

U.S. cluster munitions have arrived in Ukraine, according to Joint Staff Director for Operations Lt. Gen. Douglas Sims.

Sims said that in contrast to Russia, Ukraine is aware of the possible danger to civilians, and does not intend to use them near population centers.

"I don't think that Ukrainians have any interest in using the cluster munitions anywhere near the civilian population, unlike the Russians," Sims told reporters.

-ABC News' Matt Seyler

Amid fears Russia might blow up the Zaporizhzhia nuclear power plant, Ukraine is holding drills to prepare emergency services with how to deal with a potential radioactive disaster.

ABC News was invited to the drills in the city of Zaporizhzhia this week, about 30 miles from the plant, where firefighters in hazmat gear simulated decontaminating people from radiation during an evacuation.

Emergency workers demonstrated scanning civilians with Geiger counters as they disembarked buses, stripping some civilians and hosing them with water as they lay on stretchers. Firefighters in yellow suits sprayed down vehicles and moved them through a large washer system rigged up between fire trucks.

This week, Ukraine's chief of military intelligence, Kyrylo Budanov, claimed Russia had now completed preparation to potentially sabotage the plant if it chooses.

Read more about the drills here.

-ABC News' Patrick Reevell