Guwahati, Nov 17 (IANS) P. Krishna Rao, an engineer from Andhra Pradesh who was abducted a month ago by militants of the outlawed National Democratic Front of Bodoland (NDFB), was released Tuesday morning in Assam's Kokrajhar district, officials said.

Rao, who was kidnapped Oct 16, was released at 9.15 a.m. He is safe, but exhausted and looked frail. Rao was project manager of Gayatri Construction Company engaged in four lane highway construction work in Kokrajhar district.

A police spokesperson said Rao was let off by some NDFB militants on a highway near Karigaon in Bongaigaon district, 230 km west of Assam's main city of Guwahati.

Rao then boarded a bus and reached Kajalgaon, the district headquarters of adjoining Chirang district.

'After reaching Kajalgaon he straightaway came to his company office and then police were informed about his release by some of the staff of Gayatri Construction,' the official said.

'We have not spoken to him about the abduction as yet. First we need to get a thorough health check up as he looks a little frail and exhausted.'

A police team whisked Rao away to Guwahati under heavy escort.

'Maybe after a preliminary health check up, Rao would be leaving for Hyderabad from Guwahati airport later Tuesday,' the official said.

Rao, 50, hails from Gannavaram in the coastal Krishna district of Andhra Pradesh and was a diabetic requiring constant medication.

'What appears from the initial conversation with Rao was that he was treated well by the captors and his medical needs were taken care of during the past one month in captivity,' the official said.

It was not immediately known if his family or officials of the Gayatri Construction Company paid any ransom money to the NDFB to secure his release.