Tofazzal Hosain, the district's deputy police chief, told AFP that several people had taken part in the attack and some had been armed with machetes - a hallmark of recent attacks in Bangladesh. "They first threw a small bomb targeting police and then attacked them with machetes. Police retaliated by returning gunfire," Hosain said.

Last weekend, 20 people, including 18 foreigners, were hacked to death at the Holey Artisan Bakery in Dhaka.