Kidnapped ONGC employee Ritul Saikia was released by ULFA(I) militants on Saturday morning in Myanmar near its border with India's Nagaland, police said.

Saikia, kidnapped on April 21, was released near the border in Longwa village of Mon district in Nagaland after 31 days, a top official at Assam Police headquarters told PTI.

He was released around 7 am on the Myanmar side and he walked around 40 minutes to cross to the Indian side, the Additional DGP-ranked official said.

"Saikia has been taken to the Mon police station by the Army and Nagaland Police. A team of the Assam Police is also present there and doing the formalities to bring him back home by today evening," he added.

The released ONGC staffer looks hale and hearty, a medical check-up will be done before dropping him at his home in Titabar of Jorhat district in Assam, the senior police official said.

Following the release, Assam Chief Minister Himanta Biswa Sarma said that he hopes an era of peace and development is firmly established in the state with the cooperation of one and all.

"Heartily welcome release of Ritul Saikia, ONGC employee abducted by ULFA, early today! Grateful to Honble UHM @AmitShah (Union Home Minister Amit Shah) for constant guidance. Hope an era of peace & development is firmly established in state with cooperation of one and all. Pray to Almighty for His Blessings," Sarma tweeted.

Three employees of the Oil and Natural Gas Corp (ONGC) were on April 21 kidnapped by ULFA(I) militants from the Lakwa oilfield in Sivasagar district along the Assam-Nagaland border.

Two employees, Mohini Mohan Gogoi and Alakesh Saikia, were rescued on April 24 after an encounter near the India- Myanmar border in the Mon district of Nagaland, while the search for Saikia was on.

Hours after Sarma visited Saikia's home on May 18 and assured his wife and parents about the government's effort to bring him back, ULFA(I) chief Paresh Barua confirmed the custody of the kidnapped person.

On May 20, Sarma in a press conference appealed to Barua to release the kidnapped ONGC employee and said the Assam government will pressure the oil companies to invest more for the progress of the state.

While the official press conference was underway, Barua made phone calls to local TV channels and announced to release Saikia in less than seven days.

In the calls, Barua praised Sarma and said Assam never had such a "dynamic" chief minister for decades.

The chief minister, on the other side, welcomed the three-month unilateral ceasefire declared by the ULFA(I) and urged Barua to come to the discussion table.

In the first week of April, two employees of the Quippo Oil and Gas Infrastructure were released by ULFA(I) after three-and-half months of their kidnap on December 21 last year.

The duo was kidnapped from Kumchaikha hydrocarbon drilling site in Changlang district of Arunachal Pradesh with a demand for a ransom of Rs 20 crore.