A young tourist with a leg stuck between rocks on a raging river during a storm was rescued in Thailand.

Nong Ruangsak, 17, was splashing on the river with his friends when a muddy flash flood gushed down nearby King Pho waterfall in Mukdahan province on July 9.

The youngsters fled as the muddy deluge filled the river but the frantic teenager was swept away until his leg was caught between two large rocks.

A second team of rescuers had to be called for backup to free the young lad, who was finally removed from the rocks after more than three hours.

Rescuer volunteer Natthiya Yothaka said: ‘The locals called at around 4 pm and we were able to remove him by 7 pm. It was one of the toughest rescue operations we have done. We were relieved that the boy is safe now.'

A team of rescuers held the boy to prevent him from being swept away by the water, while the others took turns using a crowbar and a hammer to smash the rock.

The team carefully chiseled down portions of the rocks to extract the apparently nervous boy who was clinging to his saviours the entire operation.

The teenager was rushed to Khao Wong Hospital where he was given a health check but medics confirmed he was unhurt and generally healthy.

Thailand and other countries in Southeast Asia such as Malaysia, Indonesia, Myanmar, and the Philippines are at the start of their tropical monsoon rainy season, which lasts until late November.

Soaring temperatures reaching 35 degrees Celsius are often followed by powerful tropical storms with thunder, lightning, rain and flash floods which cause rivers to flow faster and become dangerous.

Many of the under-developed nations struggle to cope with the heavy rain due to chronic under-investment infrastructure and high levels of corruption funnelling away public funds away from projects such as roads and drainage.

Thailand was ranked 110 out of 180 on Transparency International's 2021 Corruption Perception Index. Denmark, Finland and New Zealand were ranked joint first place while South Sudan was bottom.