A man is being questioned over the death of one child and injuries to another who were hit by a car which crashed through a fence and on to a sports pitch.
The pair were struck at Kendal rugby club at about 17:00 GMT on Wednesday, Cumbria Police said.
The male driver, who is aged in his 40s, was arrested at the scene on suspicion of causing death by dangerous driving.
Tim Farron, the MP for the area, described the crash as “devastating, utterly heartbreaking news”, adding: “Our community in Kendal is stunned and in mourning.”
There was a police presence at the rugby club into the night, with officers saying the car involved was a black BMW i40.
The Reverend Canon Shanthi Thompson, from Kendal Parish Church, said a moment of silence was held after its Ash Wednesday service “because it’s so hard to find the words to say at a time like this”.
“Kendal is a very close community and many, many people will have links to the rugby club and people will know the children involved,” she told Radio Cumbria.
At the scene
Jennie Dennett, Radio Cumbria
The sunrise here is lighting the frosty pitch and the very wrong sight of two buckled fence panels that are pitchside, opposite the clubhouse car park.
The green panels have bent right over in front of the drop down to the pitch and there is blue and white police tape across the gap in the fence.
It’s an indication of the awful consequences of yesterday’s crash.