A 12-year-old boy is dead and his 10-year-old sister suffered critical injuries after they were struck by a vehicle in Port Hope Wednesday morning.

The Ontario Provincial Police said they were called to a collision on the 7th Line, west of Woodvale School Road, shortly after 8 a.m.

Speaking to CP24, OPP Sgt. Jason Folz said a car travelling north slid, hitting the siblings who were waiting for their school bus.

The boy was pronounced dead on the scene, Folz said. His sister was airlifted to SickKids hospital in critical condition.

"I can't even imagine how (the family is) doing. I mean, this is certainly a significant tragedy for this community and specifically for that family," he said.

Investigators will be looking into whether road conditions played a factor in the crash.

Folz said it is not known how many children were waiting for the bus at that location at the time.

n a letter to parents, the principal at St. Anthony Catholic Elementary School said the victims were students at the school.

"We don't have the words to express our shock and sadness over the tragedy of this terrible event. The family has asked for everyone's prayers at this time," Principal Karen McCormack said.

"The students were shocked. The students are sad."

The flags at all schools in the Peterborough Victoria Northumberland and Clarington Catholic District School Board have been lowered to half-mast as a sign of respect.

Pepe Garieri, a superintendent at the board, said the family is well-known in the community, and the tragedy has affected many people.

"The students here, many of them are in disbelief. They're in shock over what has taken place," Garieri said.

"They already miss their friends that are involved in this accident."