"Army, police, and the paramilitary troopers were deployed in strength across the state to foil rebel attacks with militants trying to step up violence in the run-up to India's Independence Day celebrations," on August 15, Assam chief minister Tarun Gogoi told AFP.

The latest violence left eight Hindi-speaking migrant workers dead on Wednesday in Assam's eastern Karbi Anglong district.

The shooting was blamed on militants of the outlawed United Liberation Front of Asom (Ulfa) and the Karbi Longri North Cachar Liberation Front (KLNLF).

"The attack on innocent civilians, particularly the Hindi-speaking workers, is nothing but acts of desperation by the militants," said LR Bishnoi, Deputy Inspector General of Police in Karbi Anglong.

Thousands of poor migrant workers from Bihar have made Assam their home over recent decades, finding jobs as fishermen, brick kiln workers or day labourers.

The Ulfa, fighting for an independent homeland since 1979, has vowed to free the state of all non-Assamese workers to protect local jobs.

In southern Assam's Cachar district, tribal militants of the outlawed Dima Haolam Daogah killed four people Tuesday after they refused to pay extortion, police said.

Ulfa militants, who killed about 80 people in January in a campaign against Hindi-speakers, were blamed for seven blasts that have left three dead and 25 wounded since Sunday.

The rebels have for years boycotted India's Independence Day celebrations to protest New Delhi's rule over the vast region, which is rich in oil, tea and timber.

The run-up to the event has always been violent, with Ulfa rebels in the past striking vital installations including oil pipelines, trains and bridges, as well as federal soldiers.