A missile strike on a mail depot in the eastern city of Kharkiv killed six people, Ukrainian officials said Sunday, as Ukraine reported a record number of bomb attacks in the southern Kherson region.

A further 17 people were wounded in the blast late Saturday, which is believed to have been caused by a Russian S-300 rocket, Kharkiv Gov. Oleh Syniehubov said on social media. All of the victims were employees of private Ukrainian postal and courier service Nova Poshta.

The Ukrainian-held front-line city has been at the heart of fierce fighting as both Moscow and Kyiv push for battlefield breakthroughs amid the looming onset of wintry conditions. Russian President Vladimir Putin launched his war against Ukraine in February last year.

In a statement, Nova Poshta said the air raid siren had sounded just moments before the attack, leaving those inside the depot with no time to reach shelter. It announced that Sunday would be a day of mourning for the firm.

Ukrainian President Volodymyr Zelenskyy described the strike as an attack on an “ordinary civilian object.”

“We need to respond to Russian terror every day with results on the front line. And, even more so, we need to strengthen global unity in order to fight against this terror,” he wrote on social media. “Russia will not be able to achieve anything through terror and murder. The end result for all terrorists is the same: the need to face responsibility for what they have done.”

Elsewhere in the Kharkiv region, three people were wounded in Russian shelling on the city of Kupiansk, Syniehubov said.

Officials in southern Ukraine said Sunday the Russian military had used a record number of aerial bombs over the country’s Kherson region in the previous 24 hours.

Natalia Humeniuk, a spokesperson for the Ukrainian military’s Operational Command South, said that 36 missiles had been recorded over the area, with some villages being hit by several strikes.

In a report released Saturday, the Institute for the Study of War said that Russian forces could be diversifying the mix of missiles, guided bombs, and drones used in strikes on Ukraine. The Washington-based think tank speculated that the change could be part of an attempt to find gaps in Ukraine’s air defenses ahead of further strikes over the winter.

Ukrainian officials also reported Sunday that two people had been killed by Russian shelling in the Donetsk region. A 58-year-old man in the village of Kalinovka died in his home, while a 61-year-old man was killed in the town of Vasiukovka from a direct hit to his car, according to the Ukrainian prosecutor’s office.

In a separate incident, Nikopol military district chief Yevhen Yevtushenko said that a 71-year-old man had been killed the previous day while fishing at a local reservoir. He said the victim had been found with a fishing rod in his hand, and accused Russian forces of deliberately targeting him with artillery fire.

Meanwhile, Moscow-appointed officials said Sunday that they had intercepted three Ukrainian missiles headed toward Russian-occupied Crimea. Vladimir Saldo, the Kremlin-installed leader of the Russian-occupied portion of Ukraine’s Kherson region, said all three missiles had been shot down.

(AP)