Thirty-two people were killed and 13 injured after their tour bus overturned on a road near Taiwan’s capital, Taipei, emergency officials say.
Pictures from the scene showed the tour bus lying on its side.
Most of those on board were local elderly tourists returning from a cherry blossom tour in Taichung, local media said.
Taiwan is considered one of the safest places in the world – but critics say safety standards need to be improved.
News agency CNA said no foreign nationals were thought to be on the bus.
A Taipei official, Tu Bing-cheng, said the incident “happened on a curve, so the bus flipped and that could be due to excess speed”.
“The whole frame of the bus changed shape” and was “crushed”, he said.
Twenty ambulances and 200 firefighters were deployed to the scene and rescuers have now extracted all of those on board, CNA added.
The emergency services are using a crane to move the bus into an upright position.
The injured have been taken to nearby hospitals.
Some family members of the deceased are at the scene, reciting prayers for their loved ones, reports say.
In July, 26 people died after a tour bus in Taiwan’s Taoyuan city caught fire.
Investigators said a suicidal driver was the cause of that fire.