GUWAHATI, June 24 ? Five persons were killed and seven others critically injured when suspected Dima Halong Daogah (DHD) militants ambushed a party of ONGC and CISF personnel near Dhansiri railway station in Karbi Anglong district around 3.30 pm today, police sources here said. A convoy of seven vehicles carrying personnel of Oil and Natural Gas Corporation (ONGC) and Central Industrial Security Force (CISF) was returning from Dhansiri area to Diphu town when the DHD militants opened indiscriminate fire on the party. Engineer RC Kakati, Joyram Timung, an employee and driver CR Hanse of ONGC along with two CISF constables died on the spot, police sources said. The critically injured, including ONGC officials M Lal, S Barbhuyan, Rajendra Prasad and two CISF constables have been rushed to Dimapur Army Hospital, police sources added. The public sector oil company is conducting some survey works in the Dhansiri area.