Three boys - aged eight, 10 and 11 - have died after falling through ice while playing on a frozen lake, police confirmed this morning.
A six-year-old boy is fighting for his life, while police continue to scour the water amid fears a further two children are missing.
The boys were among six youngsters pulled from the lake in Babbs Mill Park in Kinghurst, Solihull, in below-zero temperatures.
Emergency services were called to reports that six had fallen into the lake, and crew members plunged into the water in a desperate effort to save them.
Specialists scoured the water overnight, but officials said that because of freezing temperatures, there is little chance of survival.
This morning a blue police tent could be seen on the bank of the lake.
The four children who were pulled from the water were last night on life support after suffering cardiac arrests during the tragedy.
Confirming the devastating news, a West Midlands Police spokesperson said this morning: "Three boys have tragically died after falling into the lake at Babbs Mill Park in Solihull yesterday afternoon.
"The boys, aged 12, 11 and 8 were rushed to hospital after being pulled from the water.
"Sadly, they could not be revived and our thoughts are with their family and friends at this deeply devastating time. We’ll have specialist officers offering them as much support as we can.
"A fourth boy, aged 6, remains in a critical condition in hospital."
A huge 999 operation was launched after police, ambulance and fire crews were called to the scene, Birmingham Live reports.
One police officer had to be treated for hypothermia after going into the water to rescue the children, a press conference was told last night.
Police have not confirmed if the children were siblings or their gender at this stage, but locals say they believe they are primary school age.
A school near the huge Babbs Mill Lake search operation was closed today - with a plea for people to keep those affected "in their prayers". St Anthony's Primary School at Kingshurst tweeted last night that it would be shut today.
It was not known if it was directly affected by the incident.
Today the leader of Solihull Council broke down in tears as he visited the scene. Councillor Ian Courts said: "This is just about as bad as it can get. This is a dreadful situation.
"We are completely stunned by what's happened. We are still awaiting more news.
"Our thoughts and prayers have to be with the families in this situation. It's terrible, I can hardly imagine what the families are going through at this time."
West Midlands Ambulance Service tactical commander Cameron McVittie told reporters that the four children were in cardiac arrest when they came out of the water, and are currently on life support.
He said: "There's no clinical updates at this stage, as stated they were all in a critical condition on arrival at hospital."
He added: "Unfortunately, the children in the water were in cardiac arrest and were receiving advanced life support en route to hospital."
He said two were taken to Birmingham Children's Hospital and two to Heartlands in Birmingham.
Richard Stanton, West Midlands Fire and Rescue Service area commander, said: "When the fire service arrived at the scene, we were made aware there were up to six people in the water.
"So after rescuing the four children, we have continued the search and rescue operation to confirm whether there were any more in the water."
He said: "The specialist medical advice we have been given on the scene, given the temperature of the water, given the age of those who entered the water and the amount of time they have been in there, this would no longer be a search and rescue operation."
He added: He added: “The weather for the coming days is expected to be bitterly cold. We’d say to everyone please stay away from open water and please do not venture onto ice."
Superintendent Richard Harris, of West Midlands Police, told an emergency services press conference: “Four children were rescued from the lake and subsequently taken to hospital.
“On behalf of West Midlands Police we understand how distressing this is for families and the wider community and we are doing everything we can support all those involved.”
He added said that officers from all the emergency services went into the water to help the rescue, with a police officer subsequently being taken to hospital.
He said: “When officers first arrived on the scene, they went into the lake, together with fire and ambulance colleagues. It was a combined effort of all officers going into the lake to try to rescue them.”
The press conference heard that one of the police officers suffered mild hypothermia and is making a “full recovery” in hospital.
Photos from the scene show search teams on a boat on the lake shining torches into the water.
Yardley MP Jess Phillips tweeted: "Sending all my love to the families in Solihull and thanks to the emergency services for their continued efforts."
It comes as the Met Office issued the alerts as temperatures are expected to stay well below freezing overnight and combine with wintry showers to create icy conditions.
The Birmingham region has been hit by freezing conditions with the UK Health Security Agency (UKHSA) issuing a Level 3 cold weather alert covering England until Friday, December 16.
It has been snowing on and off in Birmingham today, and temperatures will continue to plummet as the region braces for freezing conditions.