Four people were killed as a result of Russian missile and bomb attacks on the largest cities of Ukraine

Russian drones, missiles and bombs pounded Kiev and Kharkiv, Ukraine’s largest cities, in overnight attacks, killing four people and injuring 15 in a sustained air assault, authorities said on Tuesday.

Russia has bombed civilian areas of Ukraine on an almost daily basis since its full-scale invasion of its neighbor nearly three years ago, causing thousands of casualties.

The Russian army is also actively opposing the forward defense in the east of the Donetsk region of Ukraine.

Another worrying development for Kiev officials is that Western countries say that North Korea has sent about 10,000 soldiers to help Russia’s military campaign.

President of Ukraine Volodymyr Zelenskyy was supposed to talk about this new threat at a meeting on Tuesday in Reykjavík with the leaders of Denmark, Iceland, Finland, Norway and Sweden.

Russian aircraft struck Kharkiv, in northeastern Ukraine, around 3 a.m., hitting a house and killing four people, Oleg Sinegubov, the governor of the region, said.

According to him, about 20 houses were damaged during the attack.

A few hours earlier, Russia dropped a planning bomb on the landmark building of Derzhprom in the center of Kharkiv, injuring seven people, mayor Igor Terekhov said.

Derzhprom, also known as the Palace of Industry, is included in the UNESCO World Heritage List as an example of modernist architecture.

Mr. Terekhov noted that in recent days, Russia has concentrated its attacks on Kharkiv. He urged people not to ignore air raid warnings.

Kyiv authorities reported that fragments of intercepted Russian drones fell on two districts of the city, injuring six people.

Ukraine has also used long-range drones to disrupt the Russian military machine and embarrass the Kremlin by striking targets on Russian soil.

A special forces academy in the Russian province of Chechnya was struck by drones, causing a fire that was quickly put out, according to Chechen leader Ramzan Kadyrov, a close ally of Russian President Vladimir Putin.

It was the first drone attack in the war against Chechnya, which is located about 500 miles east of Ukraine.