Singh, DIG of southwestern range, was stopped on his way from Sunabeda to Padmapur by a group of persons at around noon and asked to pay money.
He declined and asked them to disperse. As he was entering the car, the unidentified persons shot at him from behind. Seriously injured in the head, he was rushed to the government hospital here where he was declared dead, the sources said.
The driver of the police officer's car and his personal security officer were unhurt in the incident. Home Secretary Tarunkanti Mishra said in Bhubaneswar that this was the first time that an IPS officer had been killed in the state.
Singh was shot at twice and the identity of the assailants was being verified, he said. Rayagada and Koraput districts in south Orissa have been witnessing considerable naxalite activities over the past few years.
Police has launched an intensive combing operation in the area while a high alert had been sounded in the two districts, he said. The Home Secretary said the central government and the neighbouring states of Chhattisgarh and Andhra Pradesh had been informed about the incident.