Suspected Taliban militants detonated a suicide bomb then stormed a bank branch in the southern Afghan province of Helmand, Reuters reports.

The militants engaged in a battle with security forces while an unknown number of civilians were inside, police said.

A Reuters witness at the scene heard the blast and the gunfire.

Employees who escaped said that when the attack happened, the bank was busy with government workers who had come to collect their salaries.

"According to our information, there were four Taliban, one of them detonated his explosives and three are fighting with security forces,' said Farid Ahmad Obaid, spokesman for Helmand's police chief.