At least 20 people were killed Tuesday in a head-on collision between two trains in Italy, the local health authority said, raising an earlier death toll and warning 18 others were in a critical condition.

Vito Montanaro, director general of the Bari heath authority, said 20 people had died and 35 were injured in the crash on single-track near the town of Andria in southern Italy. Local authorities had earlier put the death toll at 12.