SANTIAGO DE COMPOSTELA, SPAIN (AFP) - The driver of a speeding train that hurtled off the rails killing 78 people in Spain was detained for "reckless homicide", Interior Minister Jorge Fernandez Diaz said on Saturday.

"He has been detained since 7.40pm on Thursday for the alleged crimes of reckless homicide," the minister told a news conference in the north-western city of Santiago de Compostela where the accident happened.

Police said on Friday they had detained the driver, accusing him of "recklessness" in Wednesday night's devastating crash but gave no further details. They said the driver, identified by media as Mr Francisco Jose Garzon Amo, 52, refused to answer their questions in his hospital bed and the case had been passed to the courts.

The driver would be questioned by a judge on Sunday, the interior minister added. Under Spanish law, a suspect can be detained for a maximum of 72 hours before being heard by a judge.

"There are reasonable grounds to consider that he may have been responsible for what happened, which must be established by a judge and the investigation which has been opened," he said.

The train was said to have been travelling at more than twice the speed limit on a curve when it hurtled off the rails and slammed into a concrete wall, with one carriage leaping up onto a siding.

The grey-haired driver, who reportedly boasted of his love for speed online, has been under police surveillance in hospital since the accident but he was discharged on Saturday and taken to a police station. He reportedly suffered head injuries in the accident that required stitches.