This is the bizarre moment a shirtless American tourist went on a rampage while bleeding from his neck.

The holidaymaker sparked alarm when he started screaming to himself outside a convenience store in Chiang Mai, on April 22.

Onlookers called the police after seeing the man with blood gushing from the side of his neck which was patched up with gauze.

Video shows him gesturing as he appeared to give an impassioned speech to the locals.

Officers arrived and tried to question him but he ignored them to continue his rambling.

A police spokesman said: 'The tourist was speaking incoherently so we asked others at the scene for details. We learned he was an American with a neck injury.

'He received initial treatment at the hospital but refused further care and walked out. He then started shouting in front of a convenience store. He seemed intoxicated, and we don't know how he was injured.'

The tourist allegedly calmed down later on, before police escorted him back to his hotel.

Thailand has been marred by over-tourism as the Thai government implements a visa-free scheme to boost revenue following the barren pandemic years.

However, angry locals claim the push for tourist dollars has attracted crowds of 'low-quality' visitors.