Pakistani officials say they have opened an investigation into a businessman who has been accused of blasphemy after refusing to join protests over an anti-Islam video and allegedly trying to convince others also not to take part.

Police officer Munir Abbasi says that hundreds of protesters in the city of Hyderabad who rallied against the film that mocks the Prophet Muhammad demanded businessman Haji Nasrullah Khan shut his shops in solidarity.

When Khan refused, one of his tenants said his decision supported the film.

City police chief Fareed Jan said Wednesday the protesters claim Khan insulted the Prophet.

Jan said there's no evidence to suggest this happened and said police were pressured by the mob to open the case.

Blasphemy is punishable by life in prison or death in Pakistan.