When leaders and activists from different areas of the city were going to join the progamme police attacked them and detained 10 leaders and activists, he said.
However, Nezam Uddin, officer-in-charge of Kotwali police station, said they detained seven people from Kazir Dewri area.
North Pahartali BNP general secretary Habibur Rahman Chowdhury, Akbarshah thana BNP member Mohammad Hanif and Md Anwar, BNP leader Mohammad Yusuf were among the detainees.
During the clash, several leaders and activists and a media worker were injured as police charged baton on them.
CMP's Kotwali Zone AC Mohammad Aminul Islam said the BNP men threw brickbats towards police without any provocation that triggered the clash.