Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

For the first time since the Russian invasion of Ukraine began, an ABC News crew was allowed an up-close-view of Ukrainian troops firing U.S. howitzer artillery weapons during active fighting in the country's Donbas region.

ABC News foreign correspondent James Longman and his crew were the only media outlet allowed to witness the weapons in action on the outskirts of Bakhmut in Eastern Ukraine, where Russian armed forces are slowly making advances.

The cannons are considered crucial in taking out Russian artillery positions as the Ukrainian forces battle to keep the Donbas from falling completely into the hands of the enemy, Ukrainian officials said.

A Ukrainian artillery commander told ABC News he was trained how to use the howitzers in Germany by U.S. personnel.

"It makes a huge difference because this is a NATO weapon," the artillery commander said. "It keeps the morale of our men high because with it we can work more and do a better job. Also, it demoralizes the enemy when he sees how rapid and precise we can open fire and sees the results of these attacks."

The commander said the biggest difference between the U.S. M-777 155mm howitzers and the Russian equivalent is the precision, speed and ease of operation.

"These howitzers stand lower, which makes it easier to disguise it," the commander said. "Also, it is harder to spot it when shots are fired."

He said the four-ton artillery weapons are light-weight compared to the nine-ton weapons they had been using early in the war.

"So, it takes less people to operate it. Also, it is easier to transport it (and) offload," the commander said. "Because often we fire it from areas that are not easy to get to. So weight is very important. But what is most important is that we are given lots of ammunition for these weapons. And we can work on much more targets now."

He said the howitzers' maneuverability is key to its use in the battlefield.

"We set up the piece, open fire and move rapidly to the new location, where we do the same," the commander said. "This way we can change location 12 to 20 and even more times a day. And the enemy can't understand how we work so rapidly and open fire from the areas that are not suitable for artillery."

Asked by ABC News if he is proud to be operating the weapons against Russian troops, the commander responded, "Sure I am! Sometimes when we move to new locations we meet other artillery officers and hear them, saying, 'Wow, triple sevens!

"So, we are very proud!" he said.

He said the weapons are so precise that many times troops hit targets with the first shot.

"Give us more weapons!" the commander said is his top request of the United States.

-ABC News' James Longman

Russian forces have purportedly taken control of the settlement of Metyolkino in the Donbas region of Eastern Ukraine, according to Russian military officials.

The Russian Federation Armed Forces said Metyolkino was "liberated" by units from the People's Militia of the Lugansk People's Republic with the help of the Russian army.

Russian officials claimed several units of the Armed Forces of Ukraine fighting near Lisichansky in the Donbas region "are abandoning the operation area due to low moral and psychological condition, as well as lack of munitions and logistics supply."

There was no immediate comment from Ukrainian officials.

Meanwhile, Russian troops continued to launch attacks on military targets across Ukraine, according to Russian officials.

The attacks included long-distance sea-based missile attacks on Ukrainian troops in the village of Shirokaya Dacha in the Central Ukraine, according to Russian officials. The attack was launched while Ukrainian military commanders were meeting in the village and "resulted in eliminating more than 50 generals and officers of the AFU (Armed Forces of Ukraine)," Russian officials said in a statement.

Long-range missile attacks over the past 10 days have destroyed 10 155-mm howitzer cannons and 20 armored combat vehicles Russian military officials said were sent to Ukrainian forces by Western countries. One Russian missile strike destroyed a transformer plant in Nikolayev in Southern Ukraine, according to Russian officials,

Retired Marine Capt. Grady Kurpasi has been identified as the third American volunteer fighter missing in Ukraine.

Kurpasi’s wife Soohee Kim said she last heard from him in late April. He left Wilmington, North Carolina, on March 7 bound for Ukraine, but did not know how long he would be there, she said.

Kim confirmed she is in regular contact with the Department of State and hears from them almost daily.

Alexander Drueke and Andy Huynh are also two American volunteer fighters reported missing in Ukraine.

-ABC News’ Luis Martinez and Vera Drymon

The United Kingdom announced a new wave of sanctions on Thursday targeting Russians involved in the barbaric treatment of children in Ukraine.

Maria Lvova-Belova, Russia's Children Rights Commissioner, tops the new list of sanctioned individuals for her alleged involvement in the forced transfer and adoption of Ukrainian children. She has been accused of enabling 2,000 vulnerable children being violently taken from the Luhansk and Donetsk regions and orchestrating a new policy to facilitate their forced adoptions in Russia.

“Today we are targeting the enablers and perpetrators of [Russian President Vladimir] Putin’s war who have brought untold suffering to Ukraine, including the forced transfer and adoption of children,” U.K. Foreign Secretary Liz Truss said in a press release.

More than 900 children were injured in Ukraine as a result of the full-scale armed aggression by the Russian Federation, according to the Ukrainian Prosecutor General’s latest report. Over 320 children were killed and more than 580 were injured.

These figures are far from being final, with more information slowly trickling in from places of active hostilities, as well as the temporarily occupied and liberated territories.

The UK's sanction list also includes Patriarch Kirill, the head of the Russian Orthodox Church, for his support and endorsement of Putin’s war.

Several members of Putin's political elite, along with four Military Colonels from a unit known to have killed, raped and tortured civilians in the Ukrainian town of Bucha, appear on the list too.

“Putin’s allies continue to choose to turn a blind eye to alleged war crimes and support his bloody offensive,” the U.K. government said. With Putin’s aggression reaching beyond Ukraine as Russian exports fuel conflict across the globe, the official press release read, the new sanctions also hit Myanmar’s military Junta.

The Junta relies heavily on Russian air assets and limiting it will cut Putin off from profiting from sales that fund his war machine, the U.K. said.

-ABC News' Edward Szekeres, Yuriy Zaliznyak, Yulia Drozd and Max Uzol