Sources said the trouble began at noon when Jubo Dal activists swooped on the local Jubo League leaders, including General Secretary of Sadar uapzila unit Mizanur Rahman Monir, who were organising party activists to join the ongoing opposition's long march towards Dhaka.

Witnesses said five shops and local Jubo Dal office were ransacked during the clash.

Of the injured, Jubo Dal leader Nasiruddin Swapan, 30, was admitted to Patuakhali General Hospital, while others were admitted to different hospital and clinics.

A tense situation is prevailing in the area. Additional police have been deployed.