(NEW YORK) — As Russia continues its nearly 16-month-long invasion of neighboring Ukraine, political turmoil has erupted in Moscow while Kyiv tries to take back territory.

A feud between Yevgeny Prigozhin, head of the Russian paramilitary organization Wagner Group, and Russia’s top military brass escalated as Prigozhin’s forces left the front line in Ukraine and marched across the border to seize a key Russian city. They then marched north toward Russia’s capital, seemingly unopposed, before turning around just hours later. The short-lived rebellion was described by international observers as the most significant challenge to Russian President Vladimir Putin’s authority in his more than 20 years of rule.

Meanwhile, Ukrainian troops are in the early stages of a counteroffensive to reclaim the almost one-fifth of Ukraine’s territory that is under Russian control.

Here’s how the news is developing. All times Eastern:

Jul 25, 1:00 PM EDT
Pentagon announces new $400M aid to Ukraine

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

Jul 20, 4:04 PM EDT
Ukraine begins using controversial cluster munitions provided by US

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

Jul 19, 9:47 PM EDT
Russian strikes hit Mykolaiv and Odesa, multiple people injured

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.

Copyright © 2023, ABC Audio. All rights reserved.