Russia made good on its threat to retaliate against Ukraine for bombing a Kremlin tanker, unleashing a massive and deadly missile and drone strike Sunday.

Ukrainian military officials confirmed that waves of 70 Russian drones and missiles were launched over the Caspian Sea to lay waste to cities in western Ukraine.

The overnight blitz and counterattack killed at least six people.

Ukrainian President Volodymyr Zelenskyy condemned the Russian strike, noting one of the bombs hit a blood transfusion center in Kupyan in the Kharkiv region.

“This war crime alone says everything about Russian aggression,” Zelenskyy said. “Defeating terrorists is a matter of honor for everyone who values life.”

Kyiv officials said the shelling in the Kharkiv region killed two people, including a 58-year-old woman, and left four others injured while also igniting a forest fire.

Two people were reported dead in the Donetsk region, according to local governor Pavlo Kyrylenko.

Officials added that at least three rounds of bombings also hit the Starokostiantyniv area and an aircraft engine manufacturing building in Zaporizhzhia.

Kyiv said it shot down 26 of the drones that were deployed.

Meanwhile, in the Russian-controlled city of Donetsk, the Kremlin-appointed mayor Alexei Kulemzin said the Ukrainian counterattack killed a woman in her 80s and set fire to a university building.

Russia’s Emergency Situations Ministry said the blaze caused the school’s main building to collapse, but reported there were no casualties.

During the weekend bombings, Russia suspended flights at Moscow’s Vnukovo airport after a Ukrainian drone was shot down in the city’s airspace.

It was the first time flights were halted in the area after two drones crashed into the Moscow City business district on July 30.

The latest aerial strikes came after Russia promised to hit Ukraine hard in the wake of a Kyiv drone — strapped with nearly 1,000 pounds of TNT — struck a Russian tanker in the Black Sea on Saturday.

“The Sig tanker … suffered a hole in the engine room near the waterline on the starboard side, presumably as a result of a sea drone attack,” Russia’s Federal Agency for Marine and River Transport said on Telegram. The post added that there were no deaths among the 11 crew members.

Russian Foreign Ministry spokeswoman Maria Zakharov called the attack “barbaric” and warned the “perpetrators will inevitably be punished.”

With Post wires