Putin on July 4 declared that Russian forces "must carry out their tasks according to previously approved plans" and said they should continue to advance throughout the region "as has happened in Luhansk."

Ukraine's forces withdrew from the bombed-out city of Lysychansk late on July 3, prompting Russia to claim full control of the eastern Luhansk region, although Ukrainian President Volodymyr Zelenskiy vowed to regain the lost ground.

"If the commanders of our army withdraw people from certain points at the front, where the enemy has the greatest advantage in fire power, and this also applies to Lysychansk, it means only one thing -- that we will return thanks to our tactics, thanks to the increase in the supply of modern weapons,” he said in his nightly video on July 3.

After failing to take the capital, Kyiv, Russia revised its military focus on Ukraine's east with the goal of capturing the Donbas, which is composed of the Luhansk and Donetsk regions.

The General Staff of the Ukrainian military said on July 4 that the Russian forces were currently focusing their efforts on pushing toward the line of Siversk, Fedorivka, and Bakhmut in the Donetsk region.

The Russian Army has also intensified its shelling of the key Ukrainian strongholds of Slovyansk and Kramatorsk deeper in Donetsk.

On July 3, six people, including a 9-year-old girl, were killed in the Russian shelling of Slovyansk and another 19 people were wounded, local authorities said. Kramatorsk also came under fire on July 3.

Earlier, Russian Defense Minister Sergei Shoigu reported to Putin that the Russian military had taken the entire territory of Ukraine’s eastern Luhansk region, the Russian Defense Ministry said, according to TASS.

In acknowledging the withdrawal from Lysychansk, Ukraine’s military command said it had decided to pull back to save the lives of its soldiers.

Luhansk regional governor Serhiy Hayday told Reuters on July 4 the withdrawal from Lysychansk had been "centralized" and orderly, and was necessary to save the lives of Ukrainian soldiers who were in danger of being surrounded.

"In terms of the military, it is bad to leave positions, but there is nothing critical [in the loss of Lysychansk]. We need to win the war, not the battle for Lysychansk," Hayday said.

"It hurts a lot, but it's not losing the war,” he said, adding that he expected Slovyansk and the town of Bakhmut in particular to come under attack.

"Still, for them goal No. 1 is the Donetsk region. Slovyansk and Bakhmut will come under attack; Bakhmut has already started being shelled very hard,” he said.

Meanwhile, on the diplomatic front, Zelenskiy and Prime Minister Denys Shmygal spoke to a conference in the Swiss city of Lugano about the need for the international community to support Ukraine as it attempts to rebuild from the destruction caused by the war.

Shmygal, in a rare trip outside of Ukraine since the start of the conflict, told the summit that "we believe that the key source of recovery should be the confiscated assets of Russia and Russian oligarchs," which he estimated at $300 billion to $500 billion.

"The Russian authorities unleashed this bloody war. They caused this massive destruction and they should be held accountable for it."

Zelenskiy, speaking via video link from Kyiv, said the reconstruction efforts in his country were a service to the entire globe.

"To rebuild Ukraine is to restore the principles of life, to restore the spaces of life, to restore what makes people human," he said.

With reporting by Reuters, AP, TASS, and dpa