A case has been filed against 22 BNP men, including its Phultola upazila unit Convener Prof Gazi Abdul Haque, under the Explosives Act in Khulna.
Sadar police station Sub-Inspector Rafiqul Islam lodged the case on Saturday against 17 named and four to five unnamed people for obstructing government work.
BNP called a sit-in programme in cities, thanas and upazilas across the country on Saturday.
As part of the programme, BNP men gathered on Jamira Road at 11:30am under the leadership of Abdul Haque.
At that time, the law enforces stopped them as they did not have permission to hold the programme, police said.
Meanwhile, nine BNP leaders and activists, including Khulna metropolitan BNP Joint Convener Kazi Md Rashed, have been released from jail on bail in various cases filed by the police.
They were released from prison on Sunday afternoon.