The crash occurred about 11am in the southern Puglia region between the towns of Ruvo di Puglia and Corato.
An aerial picture from the scene, distributed by Italian firefighters, showed the smashed remains of train cars and a large area of scattered, twisted metal at the impact site.
At least ten people were reportedly killed and dozens injured after two passenger trains collided in Puglia in southern Italy on 12 July.
The local newspaper reported that among those rescued was a small child who was taken to hospital in a helicopter.
National police and Carabinieri couldn't immediately give details about the extent of the crash, saying they were in the middle of responding.
Prime Minister Matteo Renzi interrupted a speech in Milan to say the country would "not stop until we know what happened".
The chief of the firefighting service in Bari said 10 people had been killed and dozens injured.
Ansa said ambulances and fire trucks were arriving at the scene.