BANGKOK, March 25-- Three Chinese tourists, two females and one male, were killed after a bus crashed in Thailand' s Phuket Island on Wednesday morning, China's consular office in Phuket said.

At around 11:40 a.m. local time, a tour bus, which was carrying 18 Chinese tourists, a local guide and a driver, rolled over and plunged into the valley after its brakes failed, according to the office.

Three of the 15 injured Chinese tourists were severely wounded and advised to remain in the hospital for further observation while the others were slightly injured.

Those three suffered external injuries and need not be under intensive care, the office added.

This is the first day in Phuket for the tour group from northwest China's Shaanxi province, the office said, adding families of the deceased have been notified.

The office said it would help the bereaved families come to Thailand as soon as possible and also help them negotiate with relevant parties regarding compensations.

Phuket, a most popular tourist destination in Thailand which attracts nearly 1 million Chinese visitors annually, is quite prone to accidents involving tourists.

In the first two months of this year, a total of 361 major accidents occurred in Phuket, resulting in 388 injuries and eight fatalities, local media said, citing figures from the Thai Road Safety Culture organization (TRSC).

In 2014, 4,643 accidents occurred in Phuket, causing 5,410 injuries and 78 deaths, according to the TRSC.