It was not clear whether the attack was linked in any way to other killings this year of liberals and religious minorities in the mostly Muslim nation of 160 million people.
The attack, in the south-western district of Chuadanga, targeted unorthodox religious devotees known as bauls.
“About nine to 10 miscreants with masks stormed the (bauls’) meeting place and tied up them to a tree, beat them and set fire to their shelter,” said Abu Jihad Mohammad Fakhrul Islam, the officer in charge of Damurhuda police station, 260 km (160 miles) south west of Dhaka.
Islam told Reuters the attackers threatened to kill the bauls unless they left the village, taking all their belongings, within 10 days.
He said no one had been arrested yet.
People from a similar religious group reported being attacked in the same district on July 17.