Carriages completely destroyed in a head-on collision involving two passenger trains near Andria on July 12, 2016 in Puglia, Italy. 25 people have been killed and dozens more hurt in the collision.The emergency services have been trying to free passengers from the shattered carriages. [Photo/VCG]

The crash happened at around 11:30 am (0930 GMT) on a fiercely hot summer's day.

Both trains were comprised of four carriages. The front carriages on each were pulverised as they slammed into one another. Sky Italia TV said one of the drivers had died, with no word yet about the fate of the other one.

"It looks like there has been a plane crash," said the mayor of Corato, Massimo Mazzilli.

Rescue services parked their ambulances and fire trucks among the olive trees and set up a field hospital to treat the injured. The sound of crickets rang out as the first bodies were extracted from the site in metal caskets.

"I dug through the wreckage and managed to save my husband. But I saw people cut to pieces," said an elderly woman standing alongside her husband, whose head was swathed in bandages. Another survivor said he was thrown to the floor by the impact. "When I got up, I saw hellish scenes around me."

Kicking up clouds of dust, helicopters landed in a nearby field to pick up the most seriously injured.

It was not clear how many people had been on the trains at the time of the collision. By mid-afternoon a giant crane had arrived at the scene to start lifting the smashed carriages to see if any bodies were trapped under the wreckage.

The stretch of track is operated by a small, private rail company Ferrotramviaria. Italian media said the European Union had earmarked funds to build a second track along the route but that the work had been delayed.

The last major rail disaster in Italy was in 2009 when a freight train derailed in Viareggio, in the centre of the country, and more than 30 people living close to the tracks died in the subsequent fire.