This is the dramatic moment three boys were rescued after they were stuck in the middle of an overflowing river after heavy rain in Thailand.

The youngsters were travelling to a waterfall when a muddy flash flood cascading down the mountain swept them away in Phetchabun province on September 1.

While waiting for help, the terrified teenagers huddled on a large rock in the middle of the fast-flowing river torrents until locals found them and called the emergency services.

Rescue volunteers wearing safety vests set up ropes which they tossed to the youngsters so they could tie them around their bodies and drag them through the deluge to safety.

Brave volunteer rescuer Pisit Ngernlor, 19, said: ‘The boys were visiting the Wang His Ho waterfall which is a popular attraction in the area.

‘However, they did not anticipate that there would be a flash flood since it was not raining that time. Rivers are dangerous during the monsoon season because the water from the mountains flows down very quickly and causes them to swell.'

After 30 minutes, the boys were pulled to safety and checked for injuries. Fortunately, they only had light scratches on their legs.

They were taken home by the rescuers and thanked the locals as well as the volunteers who helped them.

Thailand and other countries in Southeast Asia such as Malaysia, Indonesia and the Philippines are at the peak of their tropical monsoon rainy season, which lasts until October or November. Soaring temperatures reaching 35 degrees Celsius are often followed by powerful tropical storms with thunder, lightning, rain and flash floods.