Patna, Sep : At least three people were killed and another person was seriously injured during a violent clash between two groups over milk dues in Patna, police said on Friday. According to the police, the incident occurred late Thursday night in the city's Surgapar locality under the Fatuha police station. The injured person, Mintu Kumar (22), is admitted at the Nalanda Medical College and Hospital and his condition is said to be critical. The victims were identified as Pradeep Kumar (35), Sailesh Kumar (40) and Jay Singh (50). 'There was a dispute between two groups over some milk dues. One group reached the house of another group and demanded the money. This led to a quarrel between them and suddenly firing started,' Patna SSP Rajiv Mishra said. According to DSP Fatuha Siyaram Yadav, one group was led by Jay Singh, while the other by Pradeep Kumar. Following the incident, a large number of local residents assembled at the place and staged a protest against the violence. They also blocked the road till the wee hours of Friday. Patna police have deployed a large number of personnel to control the situation. /IANS