At least 20 people were killed and dozens injured when two passenger trains collided head-on in the southern Italian region of Puglia Tuesday.
The crash happened as the trains, each with four cars, were moving on a single track between the towns of Corato and Andria, according to police.
No immediate reason was given for the collision, which took place at around 09:30 local time on a hot summer day.
An aerial image showed cars crumpled together and forced off the track at sharp angles.
Italian Prime Minister Matteo Renzi told reporters that every effort will be made to get “a clear explanation over what happened."
Renzi cut short a visit to Milan in northern Italy to return to Rome.