LONDON

The death toll from Spain’s high-speed train collision rose to 41 on Tuesday as the country began three days of national mourning for its deadliest rail disaster in more than a decade.

The crash occurred late Sunday near the town of Adamuz in the southern region of Andalusia.

A high-speed train operated by private rail company Iryo, traveling from Malaga to Madrid, derailed and strayed into the path of an oncoming train run by Spain’s public rail operator Renfe. The Renfe train also derailed following the collision.

Transport Minister Oscar Puente told Spanish broadcaster RNE that the death toll rose Tuesday when a body was found after one of the coaches involved in the crash was removed.

More than 120 people were injured, with 39 still being treated in hospital, including four children, according to the government of Andalusia.

The cause of the accident remains unclear.

“Everything up until now has been speculation,” Puente said, adding that a team of experts is looking at whether fractured rails “were the cause of the accident or a consequence of the derailment."

Investigators also said Tuesday they will examine the sixth coach of the Iryo train, which they believe was the first to derail. Spanish police have requested that the coach be left in place where it came to rest so it can be carefully examined as part of the inquiry.

As the country marked the first day of national mourning on Tuesday, flags were flown at half-mast on public buildings across Spain.

Television presenters wore black, while ministers curtailed public appearances as a mark of respect for the victims.