A Texas pastor and his three young sons were killed in a tragic road accident that left his wife and daughter in critical condition.

Pastor Israel Avelar, of Temple Baptist Church in Lexington, died on Saturday as he travelled back to his home from a theological school with his family. His six-year-old son Matthew was also killed, alongside his other sons Daniel, 14, and Kevin, 17.

Pastor Jeff Fugate told the Lexington Herald Leader that Avelar's wife Hilda and 11-year-old daughter Kimberly are in a critical condition but improving.

A reporter told WKYT it was the worst accident he had ever seen.

"When I got on scene what I initially saw was quite a mess of an accident," said Blake Holland."[It was] probably the worst I've ever seen, several fatalities and several people injured and a lot of the vehicles that were involved you couldn't even really make out what kind of vehicles they were before the accident happened."

A statement on a local church's Facebook page asked for people to pray for his family and church in Lexington. "God makes no mistakes," it read.

The KGAS radio station reported that the Avelars' car had slowed down as a vehicle in front turned off the highway when a van hit the car from behind. The collision pushed the Avelars' car into the path of an oncoming lorry.

"He loved his church members. He loved his family. He would always call us. They were all loveable. It's some words that I just can't, to me they were like family, personal family," Rita Aleman, who worked at the theological school, told KLTV.

A funeral will be arranged for Sunday.