BANGKOK — An elderly Swiss woman was trampled to death and four other tourists were injured when elephants they were riding fought with each other in Thailand, police said Thursday.

The 63-year-old woman was thrown onto the ground and fatally injured during an elephant trek with friends in the south of the country on Tuesday.

"It happened because the elephants quarrelled with each other. One lifted its feet so the tourists fell on the ground and it stamped on her," said Lieutenant Colonel Apidej Chuaykuar, the police officer in charge of the case.

He said a total of five tourists, who were staying in the nearby resort of Phuket, were riding two male elephants when the creatures became aggressive.

The woman was pronounced dead at a hospital in Surat Thani province that evening.

She was travelling with two other Swiss nationals who were injured, according to an official source, who said some members of the group were forced to jump from one of the animals when it began running through the jungle.

Two more tourists, whose nationalities were not immediately clear, were also believed to have been injured.

The Swiss embassy in Bangkok confirmed it was aware of the situation and was providing assistance to the victims and their families