A helicopter crash in the suburbs of Kyiv has killed 14 people, including one child and Ukraine's interior affairs minister - the country's highest-profile casualty since the war began.
Ukraine has launched an investigation into the cause of the crash, but it could take weeks. The BBC has been piecing together what we know and what we don't know in the immediate aftermath of the disaster.
What happened at the crash site?
BBC Ukraine correspondent James Waterhouse has been reporting from the crash site at Brovary, a suburb on the eastern edge of Kyiv.
At the site, near to a kindergarten, he saw wreckage of the aircraft - a door panel and one of the rotors - along with three bodies covered in foil blankets.
A video of the aftermath of the crash, verified by the BBC, shows flames and smoke across a wide area between high-rise flats and another residential block. Photos also show the nearby kindergarten blackened by smoke.
As a result of a helicopter crash in Brovary Minister and Deputy Minister of Internal Affairs of Ukraine died. Emergency Service helicopter crashed at local kindergarten. 16 dead, two of them children. Terrible tragedy. pic.twitter.com/KiKR5ItDoI— Maria Avdeeva (@maria_avdv) January 18, 2023
Ukrainian officials said the glazing of a 14-storey residential building was damaged along with three cars, while the National Emergency Service building was also damaged by the fire.
An eyewitness said she heard "such a noise" before seeing "a terrible flame" and a helicopter "circling above our home".
She said the burning helicopter headed towards one of the smaller buildings in the area.
Was the helicopter under attack?
An analysis of images of the crash site by the BBC has not revealed any evidence of missile debris, and Ukrainian officials have made no mention of any missile fire.
The news agency Reuters quoted a Ukraine Air Force spokesman telling a TV broadcast that it was too early to talk about the causes. But the spokesman added: "Unfortunately, the sky does not forgive mistakes".
What were the conditions before the crash?
The helicopter crashed at about 08:20 local time (06:20 GMT), just half an hour after sunrise, according to officials. Several videos show cloudy and misty conditions.
It is thought it was travelling east towards the front line. Volodymyr Tymoshko, the head of police in the eastern city of Kharkiv, said in a Facebook post that he was due to meet the officials on board today.
However, we don't know the route the flight took before it came down as data from its location tracking device would have been blocked to avoid detection.
We have been trying to geolocate other videos purportedly of the helicopter before the crash to establish its route, but have not yet been able to verify them.
We don't know how high the helicopter was flying before it got into trouble, but the BBC's James Waterhouse says helicopters travelling towards the front line often fly at very low altitudes to avoid detection by the enemy.
"We've taken similar trips with ministers, it involved hugging treelines and occasionally vaulting over electricity pylons," he says.
Some analysts have noted there are overhead cables between buildings surrounding the crash site, which may have posed a danger to very low-flying aircraft. However, reporting from the scene, our correspondent says he has not seen any damaged cables in the area.
What do we know about the helicopter?
Ukrainian officials say the helicopter was a Eurocopter EC225 Super Puma used by the State Emergency Service. Red and white debris matching images of these helicopters can be seen in photos of the crash site.
This is not a military helicopter used in combat, and it's often used to transport members of the Ukrainian government.
Reporting team: Daniele Palumbo, Joshua Cheetham and Jake Horton