The workers from MNS' film unit Maharashtra Navnirman Chitrapat Karmachari Sena were protesting and raising slogans outside Metro Cinema in South Mumbai.
The Raj Thackeray-led party has asked the theatre management not to hold any show of 'Ae Dil Hai Mushkil' which features Pakistani actor Fawad Khan.
The MNS had given a written appeal to the theatre management urging them not to show the movie as it features a Pakistani actor. The party workers also raised slogans outside the theatre, police officials said.
"We arrested 12 MNS activists and booked them under relevant sections of Maharashtra Police Act and also CrPC," said Senior Inspector of Azad Maidan Police Station Vijay Kadam.
They were produced before a local court which granted them cash bail of Rs 5,000 each in the case (carrying out procession without permission) under the Police Act.
The MNS activists were also booked under the CrPC section 151 (3) (arrest to prevent the commission of cognisable offences) in which they did not get any relief and sent to judicial custody till November 4.
Seeking to calm tempers over opposition to the release of his directorial venture, Johar had on Tuesday made a fervent appeal against stalling the release, saying he will not engage with talent from Pakistan in future.
However, the MNS said reality has dawned late on Johar.
MNS cine wing head Amey Khopkar, after a meeting with senior party leaders and Raj Thackeray, said they were firm on opposing the release.
"We will not allow the film to be screened in single screens and multiplexes. Reality has dawned late on the producer," Khopkar said.
The MNS and some other political parties have opposed release of films with actors from Pakistan after the Uri terror attack, putting a question mark on the fate of Johar's movie, slated for release on October 28.
The Cinema Owners Exhibitors Association of India, too, decided not to screen films with Pakistani actors in four states -- Maharashtra, Gujarat, Karnataka and Goa.
A team from Johar's Dharma Productions along with filmmaker Mukesh Bhatt and Vijay Singh of Fox Star Studios had met Mumbai's top police officials and sought protection for the theatres to screen the film.
Deputy Commissioner of Police Ashok Dudhe had said, "Mumbai police will provide adequate protection to cinema theatres."
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