The head-on collision between two passenger trains, which occurred in the southern Italian province of Apulia earlier on Tuesday, has claimed the lives of at least twenty people and left fifty other injured.

The incident occurred between the coastal towns of Bari and Barletta as one of the trains was en route from the town of Corato to the city of Andria, while the other was traveling in the opposite direction.

The two trains were traveling at high speed on a single-track line at the time of the incident. The exact cause of the crash has not been established yet, but the possibility for human error among has not been excluded.

Several of the people injured in the collision are in critical condition. Surviving passengers have been extracted from the wreckage and admitted to hospitals in Andria and Barletta. Authorities inform that there is need for group O blood.

Among the survivors is a small child, who had been extracted from the wreckage and transported to hospital by helicopter.

Around 200 people have been involved in the rescue operation, with rescuers having set up field hospital to provide care to the injured.

Upon learning of the incident, Italian Prime Minister Matteo Renzi, who had been on a trip to Milan, immediately headed back to Rome.