An officer tried to punch through the ice as emergency workers attempted to reach the children.
Image source, PA MediaThree boys aged eight, 10 and 11 have died after falling into an icy lake near Solihull on Sunday.
The boys were rushed to hospital after being pulled from the water, West Midlands Police said.
It is thought they had been playing on ice in Babbs Mill Park, in Kingshurst.
In a statement on Monday, police said the boys were unable to be revived and thoughts were with their family and friends. Specialist officers were helping the families.
A fourth boy, aged six, remains in a critical condition in hospital.
Searches of the lake are continuing as police seek to establish exactly what happened and if anyone else fell into the water.
Emergency services were first called to Babbs Mill Park shortly after 14:30 GMT on Sunday, where it was reported four children had been playing on the ice and fallen through into the lake.
Members of the public and police officers initially went into the chilly waters to try to get the youngsters out, before the children were reached by specialist firefighters, who got the group to safety.