(CNN) A helicopter carrying the leadership team of Ukraine's interior ministry crashed near a kindergarten and residential block in the Kyiv region on Wednesday, killing at least 14 people, including all nine people on board, according to officials.
A further 25 people were injured following the incident in the city of Brovary Wednesday, including 11 children, Ukrainian President Volodymyr Zelensky said Wednesday.
Fourteen bodies were found at the crash site, including one child and all nine people who were on board the helicopter -- six ministry officials and three crew members, according to the State Emergency Service of Ukraine (SES).
Ukrainian National Police confirmed that Interior Minister Denis Monastyrsky, First Deputy Minister Yevheniy Yenin and State Secretary Yuriy Lubkovychis were among the dead.
The official cause for the crash has yet to be announced, and there has been no suggestion from any Ukrainian officials about Russian involvement.
"Ukraine lost the whole generation of young politicians...it's a huge grief for everyone," Anton Gerashchenko, an adviser to the Ukrainian government, told CNN on Wednesday.
When asked why the entire leadership of the interior ministry was traveling together, Gerashchenko replied: "I think this bloody lesson will be a clear example for us that such high politicians and ministers cannot travel altogether. But this tragedy brought the death of children which is amazingly horrible -- and obviously everyone who died -- every life of every Ukrainian is priceless."
The crash has stunned the country at a critical moment in the war: Ukraine has been imploring Western allies for more weaponry as Russian strikes hit its critical infrastructure and civilian populations with abandon.
Ukraine's President Zelensky called the deaths "a truly great loss for the state" later on Wednesday, adding that "hundreds of people were involved in extinguishing the fire, searching and rescuing the injured, and carrying out the initial investigative actions."
The Ukrainian Security Services launched an investigation into the crash, and posted on Facebook that "several versions of the tragedy are being considered."
They include: "Violation of flight rule, technical malfunction of the helicopter (and) deliberate actions to destroy the helicopter."
The Kyiv region had grey skies and low visibility on Wednesday, according to a CNN team on the ground. They also confirmed seeing that the helicopter that crashed was a Eurocopter EC225 "Super Puma,"after seeing remnants of flight manuals among the debris.
The Ukrainian Security Services said that this helicopter "was repeatedly involved in the transportation of personnel to emergency sites."
"The crew of the aircraft was trained to perform tasks in difficult conditions and had the required number of hours of flying time," it added in a Facebook post.
The helicopter landed near a kindergarten and a residential building, Oleksiy Kuleba, head of the Kyiv Regional Military Administration, said, adding that at the time of the crash there were children and staff in the kindergarten.
Mayor of Brovary Ihor Sapozhko declared three official days of mourning on Thursday, Friday and Saturday.
In a written statement, Zelensky called the crash "a terrible tragedy," adding that he has ordered the Ukrainian Security Services "to find out all the circumstances."
Zelensky ended his statement by saying the interior ministry officials were "true patriots of Ukraine. May they rest in peace! May all those whose lives were taken this black morning rest in peace!"
The officials are thought to be the most senior government figures to have died since Russia invaded Ukraine last February.
Monastyrsky, 42, was a lawyer by training. According to a biography published on the ministry's website, he spent some years teaching law and management at a university in his home town of Khmelnytskyi, before deciding to turn "from theory to practice" and become involved in politics.
He worked on reforming Ukrainian law enforcement following the 2014 Euromaidan revolution, rose through the ranks and was appointed interior minister in July 2021.
Last year, Monastyrsky accompanied a CNN crew on a visit to abandoned Russian military positions in Chernobyl.
News of Monastyrsky's death sparked a wave of reactions from many of his counterparts and other foreign leaders.
"Saddened by the tragic death of the Ukrainian Interior Minister Denis Monastyrsky. Thoughts for all the victims of this terrible event that occurred near a kindergarten, for the children and the families," French President Emmanuel Macron tweeted.
UK Foreign Secretary James Cleverly described Monastyrsky as "a true friend of the UK."
Charles Michel, president of the European Council, also paid tribute to Monastyrsky as "a great friend of the EU." Michel tweeted that the European Union joins Ukraine "in grief following the tragic helicopter accident in Brovary."
Yenin, also 42, served as Ukraine's deputy prosecutor general and deputy minister of foreign affairs before becoming Monastyrsky's first deputy in September 2021, according to the ministry's website.
Lubkovychis was 33 and, like the other two men, was appointed to the ministry in 2021.