Patna, July 3 (PTI) Stones were thrown and cooking gas cylinders hurled at police when they reached Nepali Nagar in Patna with bulldozers to remove encroachers from a 40-acre government land on Sunday, officials said.Police said they had to use tear gas to bring the situation under control at the colony in Rajeev Nagar area."When security personnel reached there in the morning to remove all illegal construction on the government land, locals started pelting stones. Some police officers, including City SP of Patna Ambrish Rahul, sustained injuries," District Magistrate (DM) Chandrasekhar Singh said."The district administration will remove all 90 illegal construction from the 40 acres of government land today," he said in the evening.Twelve people were arrested and videos of the violence are being analysed to identify those involved in it, Singh said, adding that the protesters also threw small LPG cylinders at the forces.Some of the gas cylinders were empty, while many were filled but those did not blast, otherwise, a major mishap could have happened, officials said.Around 2,000 police personnel were involved in the operation using 12 bulldozers, they said."Land mafia is quite active in Nepali Nagar. They first encroached on the government land and after that, fraudulently started selling them," Singh claimed."They tried their best to stop the encroachment drive. They had approached courts also. However, the court directed to make the area encroachment free," he said. PTI PKD SOM SOM