Isar Mia of Lupaura village in Sarail upazila had borrowed Tk 300 from Rabi Ullah of the same village some days ago.

On Thursday, in the afternoon, Rabi asked Isar to repay the money. After an exchange of words, they had a bout.

As this spread, their neighbours and supporters came with lethal weapons and clashed for an hour, leaving at least 50 people.

Twelve of them were sent to Sarail Upazila Health Complex, Brahmanbaria Sadar Hospital and to two private clinics in the town in critical conditions. The rest were treated at the health complex.

Sarail thana police rushed to spot and quelled the violence but did not arrest any body, police said.