Ukraine’s interior minister died Wednesday in a helicopter crash near the capital that killed at least another 14 people, including other officials and three 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 to clobber Ukraine, after a Russian missile strike on an apartment building killed dozens of civilians.

There was no immediate word on whether the crash, which was near a kindergarten, was an accident or related to the war. No fighting has been reported recently in the Kyiv area.

Ukrainian President Volodymyr Zelenskyy said the crash was “a terrible tragedy” on a “black morning.”

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

British Home Secretary Suella Braverman called 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.

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

Kyiv Regional Governor Oleksii Kuleba said 18 people overall were killed, including three children, and that 25 were injured. Ukraine’s Emergency Service, however, put the death toll at 15. It was not immediately possible to confirm if that was old information or a revised figure.

At the scene of the crash, at least four bodies on the ground were covered by reflective sheets as officials cleared helicopter debris from a kindergarten playground. Wreckage also sat on top of a charred vehicle and a building.

“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.

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.

The crash comes at a particularly dark period in the war for Ukraine, just days after the Russian strike on the apartment building in southeastern Ukraine killed 45 people, including six children — the deadliest attack on civilians since the spring.

“Another very sad day today — new losses,” said Ukraine’s first lady, Olena Zelenska, dabbing teary eyes and pinching her nose as she responded to the news while at the World Economic Forum in Davos, Switzerland.

The forum held 15 seconds of silence after opening the session to honor the Ukrainian officials killed.

“Haven’t had time to recover from one tragedy, there is already another one,” said the deputy head of the Ukrainian presidential office Kyrylo Tymoshenko.