SHILLONG/NONGPOH: East Khasi Hills Police have called in additional forces from different districts to maintain law and order in the capital city, while three more KSU activists were arrested in Ri Bhoi in connection with the protest against railway project. District Superintendent of Police Davis Marak said on Monday additional forces have already started coming and the Special Operation Team (SOT) personnel deployed in other districts have also been asked to return to Shillong. The police have also stepped up vigil on roads both in the city and the whole of Ri Bhoi district. Patrol teams with cameras were seen in Ri Bhoi on Monday. There was nakabandi at several places and vehicles were checked at every point. On the recent cases of arson, Marak said police have not been able to establish the identity of any of the perpetrators in the city. Ri Bhoi police arrested three more KSU activists on Monday in connection with the recent attack at the railway construction site at Byrnihat. The arrested persons have been identified as Johny Nongrum, Jayan Sylliang and Sabarthani alias Babloo Lyngdoh. They have been remanded in fourday police custody. A case of petrol bomb attack on a truck was reported in Umsning but the damage was less as the vehicle was covered with wet plastic. In the city, police are taking confidence building measures and all officers in charge of different police stations have been asked to organise peace meetings in their respective localities. Marak said police spoke with the KSU leadership and it was clarified that KSU had sent some people to the railway site in Byrnihat for inspection but some anti-social elements within the group started the violence. The SP also did not rule out that some miscreants were taking advantage of the situation. He stressed on the need to bring more parts of the city under the surveillance of CCTV cameras and said the process for installing 30 more cameras in Shillong under the second phase is already on.