KYIV, Ukraine >> Reinforced Russian troops backed by airstrikes pummeled a portion of eastern Ukraine on Saturday, blowing up bridges and shelling apartment buildings as they fought to capture two cities that would put a contested province under Moscow’s control, Ukrainian officials said.

Russian and Ukrainian forces battled street by street in Sievierodonetsk and neighboring Lysychansk, regional Gov. Serhiy Haidai said. Russian strikes killed four people, including a mother and child, in the nearby village of Hirske, Haidai said.

The cities are the last major areas of Luhansk province still held by Ukraine. The Russian attacks are central to the Kremlin’s reduced wartime goal of seizing the entire Donbas region, where Moscow-backed separatists have fought Ukrainian forces for eight years and established self-proclaimed republics.

Russia also escalated attacks in Donestk, the other province that makes up the Donbas, the Ukrainian military said, as the war reached its 101st day. Reflecting the close combat, Russian and Ukrainian military officers blamed each other for a fire that destroyed the main church at the Sviatohirsk monastery, one of Ukraine’s holiest Orthodox Christian sites.

In a video address Saturday, President Volodymyr Zelenskyy accused Russia of “deliberately destroying the Ukrainian culture and its historic legacy along with social infrastructure and housing — everything needed for normal living.”

In recent days, Russian forces have focused on capturing Sievierodonetsk, which had a prewar population of about 100,000. At one point, they held 90% of the city, but Ukrainian soldiers clawed back some ground, Haidai reported Friday. Zelenskyy described the city’s situation as “extremely difficult” Saturday.

Western military analysts said Russia was devoting significant troop strength and firepower to what British officials called a “creeping advance” in the Donbas.

“The combined use of air and artillery strikes has been a key factor in Russia’s recent tactical successes in the region,” the U.K. Ministry of Defense said in a Saturday assessment. The ministry warned that after launching so many guided missiles, Russia was employing unguided missiles that have “almost certainly caused substantial collateral damage and civilian casualties.”

The Ukrainian military reported that it repulsed nine attacks in the Donbas over 24 hours. The claim could not be independently verified.

While Russian forces are concentrated on the Donbas in the east, Ukraine has staged counterattacks to try to regain territory in the south.

After seizing most of the Kherson and Dnipropetrovsk regions, as well as the port city of Mariupol, Moscow has installed local administrators, offered residents Russian passports and taken other steps to consolidate its hold on occupied areas.

Russian shelling killed at least three civilians in the Black Sea port city of Mykolaiv, Mayor Oleksandr Senkevich said Saturday.

In other developments:

• Ukraine’s foreign minister denounced France’s president for saying the West shouldn’t “humiliate” Russian President Vladimir Putin.

French President Emmanuel Macron said in an interview with French newspapers Friday that Putin made a “historic error” in invading but world powers shouldn’t “humiliate Russia, so that when the fighting stops, we can build a way out together via diplomatic paths.” Ukrainian Foreign Minister Dmytro Kuleba tweeted in response: “Calls to avoid humiliation of Russia can only humiliate France and every other country that would call for it. ... We all better focus on how to put Russia in its place. This will bring peace and save lives.”

• The bodies of more than 1,300 civilians have been exhumed so far in the region around Ukraine’s capital following Russia’s military retreat from the area, Ukraine’s Interior Ministry reported Saturday. The bodies were sent to morgues for forensic examination, and some 200 of the victims have not been identified, ministry spokeswoman Alyona Matveyeva said. Since Russian forces left the region in early April, Ukrainian authorities have been collecting the dead, exhuming bodies from mass graves and collecting evidence for possible war crimes investigations and prosecutions.