The bomb was set off by unknown persons who intentionally activated it using a mobile phone when a group of 10 monks escorted by three Thai army soldiers were receiving alms on their morning rounds Tuesday.

The bomb was activated by a mobile phone as the monks stopped to receive alms in the predominantly Muslim-area Tuesday morning.

The 62-year-old monk sustained shrapnel wounds and was rushed to a local hospital. Medical authorities said he suffered minor injuries and was released after treatment.

Police found an explosive device weighed seven kilogrammes in an iron box at the bomb site and will study recordings from a closed circuit television monitoring system (CCTV) for leads on the suspects.