Two children were killed and three others were seriously injured when a horse and buggy was struck by a vehicle in southern Northumberland County Sunday night, state police said.

The deadly crash occurred about 8 p.m. on Route 225 in Jackson Township, near Dornsife, the Daily Item of Sunbury, reported.

All six people in the buggy were ejected when the 39-year-old driver, identified as John M. Koperna, 39, of Pottsville, crashed into the buggy as he headed south. Koperna told authorities that he believed he had fallen asleep before striking the buggy from behind.

A 7-year-old girl and a 9-year-old boy were pronounced deceased, one at the scene and another at Geisinger Medical Center, police said.

Ervan Zook, 34, Leah Zook, 29, and a 3-year-old boy were seriously injured and transported to GMC. A male child also suffered minor injuries, police said.

The horse pulling the buggy was killed in the crash.

Koperna was transported to the hospital with minor injuries.

State police were assisted by Trevorton Fire Co., AREA Services EMS personnel, Americus EMS Services, Geisinger Life Flight and Cartas and Pfeiffers towing.