Dozens of people were killed on Friday when a packed train derailed inside a tunnel in eastern Taiwan, the island's worst railway accident in decades.
Taiwan's National Fire Agency said at least 41 people were confirmed dead with more than 60 sent to hospital.
Two people were still trapped in the twisted carriages inside the tunnel on Friday afternoon, the agency added.
Officials said the accident could have been caused by a maintenance vehicle sliding down an embankment and striking the train before it entered the tunnel near the coastal city of Hualien.
"There was a construction vehicle that didn't park properly and slid onto the rail track," Hualien county police chief Tsai Ding-hsien told reporters.
"This is our initial understanding and we are clarifying the cause of the incident," he added.
Local media pictures from the scene showed the back of a yellow flatbed truck on its side next to the train.
President Tsai Ing-wen's office said she had ordered hospitals to prepare for a mass casualty event.
"The top priority now is to rescue the stranded people," it said in a statement.
The accident occurred on Taiwan's eastern railway line around 9:30 am (0130 GMT).
Pictures published by local newspaper UDN showed the front of the train inside the tunnel had been pulverised into a twisted mesh of metal.
Footage released by the Taiwan Red Cross showed rescuers with helmets and headlights walking on the roof of the stricken train inside the tunnel to reach survivors.
People further back in the train were able to walk away from the crash comparatively unscathed.
A live Facebook broadcast by UDN outside the tunnel showed a row of undamaged train carriages with rescuers helping passengers escape.
"It felt like there was a sudden violent jolt and I found myself falling to the floor," an unidentified female survivor told the network, saying she suffered a cut to her head.
"We broke the window to climb to the roof of the train to get out," she added.
The eight-car train was travelling from Taipei to the southeastern city of Taitung and was carrying about 350 passengers.
The accident occurred at the start of the busy annual Tomb Sweeping Festival, a long holiday weekend when Taiwan's roads and railways are usually packed.
During the festival, people return to ancestral villages to tidy up the graves of their relatives and make offerings.
Taiwan's eastern railway line is usually a popular tourist draw down its dramatic and less populated eastern coastline.
With the help of multiple tunnels and bridges, it winds its way through towering mountains and dramatic gorges before entering the picturesque Huadong Valley.
Friday's crash looks set to be one of Taiwan's worst railway accidents on record.
The last major train derailment in Taiwan was in 2018 and left 18 people dead at the southern end of the same line.
The driver of the eight-carriage train was later charged with negligent homicide. More than 200 of the 366 people on board were also injured.
That crash was the island's worst since 1991, when 30 passengers were killed and 112 injured after two trains collided in Miaoli.
Thirty were also killed in 1981 after a truck collided with a passenger train at a level crossing and sent coaches over a bridge in Hsinchu.
Apple Daily newspaper said the island's worst crash was in 1948 when 64 died.
Another crash in 1961 killed 48 while a 1978 crash left 41 dead.