BROVARY, Ukraine (AP) — Ukraine’s interior minister died Wednesday in a helicopter crash near the capital that killed more than a dozen other people, including children, authorities said.

Interior Minister Denys Monastyrskyi, who oversaw Ukraine’s police and emergency services, is the most senior official to die since Russia invaded nearly 11 months ago. His death, along with two others from his ministry, was the second calamity in four days for Ukraine, after a Russian missile strike on an apartment building killed dozens of civilians.

There was no immediate word on whether the morning crash, near a kindergarten and reportedly in heavy fog, was an accident or related to the war, but Ukrainian authorities immediately opened an investigation. No fighting has been reported recently in the Kyiv area.

Ukraine’s State Emergency Service said that 17 people were killed in the crash, including nine people who were aboard the helicopter and four children who presumably were on the ground. It said 25 people have been injured, including 11 children. Early official reports gave slightly different casualty figures, including a higher death toll.

Ukrainian President Volodymyr Zelenskyy described the crash as “a terrible tragedy” on a “black morning.”

“The pain is unspeakable,” he wrote on Telegram.

British Home Secretary Suella Braverman called the 42-year-old Monastyrskyi “a leading light in supporting the Ukrainian people during Putin’s illegal invasion.” She said she was “struck by his determination, optimism and patriotism.”

Monastyrskyi’s deputy Yevhen Yenin and State Secretary of the Ministry of Internal Affairs Yurii Lubkovych were also among those killed, according to the chief of Ukraine’s National Police. Senior officials routinely travel by helicopter during the conflict, often low and at high speed.

Nine of those killed were aboard the chopper when it crashed in Brovary, an eastern suburb of the Ukrainian capital, police chief Ihor Klymenko said. The others who died were apparently on the ground.

At the scene of the crash, which was near a kindergarten, at least four bodies on the ground were covered by reflective sheets. Officials cleared chunks of charred, mangled wreckage, lying against an apartment building and in a playground. Some walls were partly demolished and blackened.

“It is too early to talk about the reasons,” for the crash, the spokesperson for Ukraine’s Air Forces, Yurii Ihnat, told a television channel. He said an investigation could take some time.

The helicopter was a Super Puma supplied by France, he added.

A French defense official said the helicopter was sold to Ukraine in 2019 and was not part of equipment that France has provided since the start of the war. He spoke on condition of anonymity because he was not authorized to be named, according to ministry policy.

The Security Service of Ukraine is conducting an investigation, prosecutor general Andriy Kostin said. “For now, we are considering all possible versions of the helicopter crash accident,” he said on Telegram.