"If the MNS workers commit any cognizable offences like assault then they will not be forgiven and action will be taken against each one of them," joint commissioner of police (law and order) K L Prasad told PTI.
Prasad was responding to a letter sent by Thackeray asking the police to 'think twice' before taking action against MNS activists involved in the agitation to enforce the civic body's deadline stipulating Marathi signboards on the city shops by August 28.
According to Prasad, Thackeray through his political party is trying to trap Mumbaikars under the garb of regionalism to gain political mileage.
"Regionalism should not be dragged by political parties on such issues and all the people in the city are working for the development of the country," Prasad said.
He also added that if MNS activists resort to violence or assault on Thursday then stringent action would be taken against them.
Stepping up his campaign for Marathi signboards, Thackeray warned that shop owners who do not put up the boards by Thursday will have to face the wrath of his men.
Dismissing the conception that the MNS is raising the issue of Marathi signboards for electoral gains, Thackeray had said that their agitation is for Marathi pride.