Visitors enjoying a riverside barbecue fled for cover after two groups exchanged gunfire, ending in the death of two men and injuries to three boys caught in the crossfire. Some 36 bullet casings were recovered at the scene.

Police were alerted to the gunfight at the Ban Chuk Kraphrao sluice gate in Dan Makhamtei district at 10.30pm on Saturday. One man was killed on the spot and another found dead on Sunday morning.

Police said the dispute started when a group led by Phatchara Phuangklang went to ask another group, led by Khanchai Pradupsuk, to turn down their music.

The two groups exchanged words before police arrived and apparently restored calm. 

Khanchai and his friends left on their motorcycles. When they returned 30 minutes later, police said, Khanchai shot Phatchara, killing him instantly.

Phatchara's friends then returned fire, prompting other visitors in the area to run for cover. Khanchai was shot and fell into the water. His body was recovered on Sunday morning. The remaining members of the feuding groups then fled the scene.  

The Ban Chuk Kraphrao sluice gate, which controls irrigation water from the Mae Klong River, is a popular picnic and barbecue location on weekends.

The Ban Chuk Kraphrao sluice gate on the Mae Klong River in Dan Makhamtei district in Kanchanaburi is a popular hangout on weekends.

A witness to the shooting said she and others ran for safety when the first shots rang out, and that the gunfire continued for almost five minutes.

Three boys aged 13-15 were caught in the crossfire and sent to hospital. It was unclear how seriously they were hurt.

Police and forensic experts returned to collect evidence at the sluice gate on Sunday.

Pol Capt Alongkorn Ouifuk, a duty officer at Dan Makhamtei police station, said they found 36 shells from 9mm bullets scattered throughout the area.

He said authorities are hunting for the remaining gunmen.