At least 32 people were killed after a tour bus overturned on a highway in Taipei on Monday evening, according to local authorities.The bus was carrying 44 people, including the driver and a tour guide. Most of the passengers were seniors, Xinhua news agency quoted local fire department as saying.Among the dead, 30 were killed on the spot and two others died in hospital. The other 12 people are being treated in hospital, according to the fire department.There were no tourists from the Chinese mainland or foreign countries on the bus, local police said.Local authorities are investigating the cause of the accident.