AHMEDABAD: A rally to condemn the anti-Islam film ' Innocence of Muslims ', which has irked Muslims across the globe, took a violent turn in the city on Wednesday. An angry mob set fire to the Karanj police chowky along with 11 motorbikes and two jeeps belonging to the policemen. City police fired three rounds in the air to disperse the mob. Officials also lobbed more than 30 tear gas shells and lathi-charged the protesters to bring the situation under control. At least 12 people were injured in police lathi-charge. More than 100 people were arrested for the violence by late evening. This included a woman, Zarina Khan , who had initially sought permission for a rally from the cops, which was turned down. The accused have been booked for attempt to murder and vandalism. The violence sparked off after a string of bandh calls given by various groups in different parts of the city during the past week. Several minority-dominated parts of Ahmedabad had witnessed spontaneous bandhs and small rallies against the film. On Wednesday, a large section of the minority community had decided to stage a rally on a much larger scale. However, the city police denied them permission. Upset with the decision, the protesters called for a city-wide bandh. The protesters were also angry with some of their community members. On Tuesday, Mufti Shabbir Ahmed of Jama Masjid, members of organizations like Jamat-e-Islami, Jamiet-e-Ulaima Hind and Muslim legislators and municipal councilors had appealed that the community not follow the call of bandh. In a meeting held at the Jama Masjid, Muslim leaders had condemned violent means of protest against 'Innocence of Muslims'. They also appealed to the people to not resort to violence that could disturb peace of the city. Joint commissioner of police, A K Sharma, who is in charge of the special branch, said, "We had received a letter seeking permission for this rally. We had turned it down because we felt the event could cause a law-and-order problem. We will initiate legal action against these people who defied the directive." These twin aspects did not go down well with the bandh and rally supporters who started collecting at the Lal Darwaja in huge numbers at 2 pm. The city police seemed to have underestimated the threat-perception of this massive gathering. This was evident in the fact that quite a small number of Karanj policemen were posted near Lal Darwaja and they proved to be grossly inadequate to stop the protesters from marching ahead. At around 3 pm, a huge rally marched to Jama Masjid beyond Teen Darwaja . Outside the ancient mosque people started shouting slogans against the people who had asked the protesters to stay calm. This sparked off more violence. Joint commissioner of police Ajay Tomar later said, "I have no knowledge of police firing. Whether the attack on the police was pre-meditated or spontaneous is now a subject of investigation." Ahmedabad: The angry mob refused to budge from in front of the Jama Masjid despite repeated warnings by police. Then city police lathi-charged the protesters. This triggered more violence as the mob retaliated with pelting stones at the cops. The mob then directed its fury at the Karanj police chowky, close to the women's station. As the mob started vandalizing the chowky, women officers and other cops fled in fear. The mob then set fire to the furniture and vehicles parked outside. Senior cops - joint commissioner of police Ajay Tomar and deputy commissioner of police Himanshu Shukla along with assistant commissioner of police Nirlipt Rai with 1,000 police jawans rushed to the spot. Immediately afterwards the city cops started a combing operation to hunt down those responsible for the violence. When the police were busy in crowd control near Teen Darwaja, another group of violent protestors attacked a government vehicle near Relief Cinema and set it ablaze. Nobody was injured in the incident. tnn Cops had no intel State Intelligence Bureau (SIB) and city police officials were unable to read the seriousness of developments like the bandhs and rallies preceding Wednesday's violence. A senior city police official said: "All SIB policemen are now on focused on assembly elections. This is one of the main reasons why nobody noticed the developments." Wrong arrests? Residents of Karanj alleged that several innocent people had been arrested by the city police when it took up a combing operation after the rioting. "Policemen forced their way into several houses in Karanj and some of our relatives were arrested even though they had not stepped out during the violence," said a Karanj resident. Some women had also tried to stop the police van which was being used to take away the arrested.