At least 20 people have been injured in south-western Bangladesh as a hardline Islamic group enforces a general strike to back its demands for an anti-blasphemy law.

Police and Somoy TV station say the violence on Monday took place in Chittagong city when activists from Hifazat-e-Islam clashed with ruling Awami League supporters.

Police official Abdullahel Baki says the Hifazat-e-Islam protesters threw stones at police and the ruling party supporters.

The TV station says one ruling party member was hit by a bullet, but it was not immediately clear who fired it.

The Hifazat-e-Islam protesters also blocked a rail line in eastern Brahmanbaria district to disrupt train services.

The government says it has no plans to enact an anti-blasphemy law or meet other demands from the protesters.