Maharashtra Navnirman Sena (MNS) chief Raj Thackeray was put under preventive arrest by the Mumbai police, one-and-a-half hours after his party started a road blockade across the state on Wednesday morning to protest tolls.

He was released two hours later and called off his agitation after an assurance of talks with Chief Minister Prithviraj Chavan on Thursday morning. Incidentally he had rejected the offer of talks on Tuesday and decided to continue with his agitation.

Barring a few incidents of stone throwing and the temporary closure of shops, the state remained calm. Around 12,000 MNS activists were detained across the state.

Mr Thackeray was arrested at Chembur while enroute to the Vashi toll naka, one of the entry points to the city. His wife Sharmila Thackeray led a protest outside the police station where he was held.

Mr Thackeray was charged under Section 68 and 69 of the Maharashtra Police Act which prevents "unlawful assembly."

"We wanted to prove a point to the government and we have done that. I appeal to my workers to remain calm," Mr. Thackeray said after his release.

Mr Thackeray's arrest and rapid release sparked allegations of a deal with the ruling Congress-NCP government. "The Congress and NCP are using the MNS against us. They want to divide our votes, which they have done earlier as well," alleged BJP spokesperson Prakash Javdekar.

The MNS has denied the allegations. "We are raising this issue consistently. We are not bothered by what BJP is saying as our protests will continue," said Nitin Sardesai, MNS MLA.

Earlier in the day, Mr Chavan had dismissed Mr Thackeray's agitation. "There is no need for violence. They should not politicise the issue. We have invited him for talks," he said. The Nationalist Congress Party called the agitation a "political stunt".

Mr Thackeray had announced that Wednesday's protest would not be violent and would target only highways. However, the police took no chances and there was tight security at toll booths.

Over 1.8 lakh policemen were deployed across the state. Contingents of the Rapid Action Force (RAF) and State Reserve Police Force (SRPF) were also deployed.

The police say the arrest was pre-planned. "We decided to arrest him in Chembur because few of his supporters were present and the police station is on an inside road. After his arrest, we sealed all the entry routes to the station," police sources told The Hindu.

The MNS started its agitation two weeks ago, after Mr Thackeray directed party workers to attack those who demanded tolls. The MNS then attacked toll booths across the state. Three cases have since been lodged against Mr Thackeray in Pune and Mumbai.