Guwahati • A tribal group in the northeastern state of Assam has held state-owned Oil India Ltd (OIL) to ransom with production of crude oil and natural gas being hit yesterday following an oil blockade, the third this month, officials said.

The 36-hour oil blockade by the All Assam Muttock Yuba Chatra Sanmelan (AAMYCS), which began at 6 am on Sunday, has also seen acts of vandalism with protesters damaging two OIL vehicles, besides other stray incidents during the past 36 hours, a police spokesman said.

AAMYCS has been pressing OIL to announce a Rs10bn ($253m) economic package for the Muttock ethnic group, who dominate certain areas where the company operates in eastern Assam.

"Oil production has been hit and several operational sites were forced to shut down as we were unable to send our workers due to the strike," Phanindra Dev Choudhury, an OIL spokesman, told IANS over telephone. "We are yet to assess the production loss. It would be quite substantial," Choudhury said.

The same group had resorted to a similar 36-hour oil blockade from the morning of December 9, forcing OIL authorities to shut down an oil collecting centre at Dikom, besides restricting movement of operation-related vehicles and machinery in drilling sites in eastern Assam's Dibrugarh and Tinsukia districts.

On December 6, the AAMYCS had its first oil blockade this year when miscreants had set an OIL vehicle ablaze, damaged several oil tankers and assaulted three officials working for the oil major.

The police had arrested eight youths on that occasion belonging to the minority Muttock community in connection with the vandalism.