Several local organisations, among them a key separatist guerrilla group, gave migrants from neighboring Bihar a deadline of seven days within which to leave Assam, as a dispute triggered by competition for jobs flared into violence.

"You can say many parts of Assam are on fire," said a senior police officer who declined to be identified.

Four women and two children belonging to one family were hacked to death and their home set alight in the town of Dibrugarh, about 250 km (155 miles) from Guwahati, a key city in the oil- and tea-rich state of Assam, a police spokesman said.

About 10-15 persons, armed with knives, stormed into the house of Uma Kant Tewari, a small businessman, at Kheronipathar under Tingkhong police station and hacked to death his wife, two minor daughters, a son, a niece, and a nephew, police said.

The assailants set the house on fire before escaping, police said, adding, Tewari managed to escape unhurt.

Thousands of people sought shelter in police stations across Assam, which is also torn by a 25-year-old insurgency, as crowds targeted Biharis, setting fire to their homes built of wood and roofed with tin.

The mobs looted houses, assaulted the people living in them and then set them on fire using petrol and kerosene.

Police also discovered two unidentified bodies wounded with sharp objects on the streets of the eastern town of Tinsukia early on Wednesday. Soldiers patrolled Tinsukia and Dibrugarh, the two districts worst affected, in a bid to restore calm.

In neighbouring Tinsukia disrict, two bodies of Hindi- speaking people were recovered from Tinsukia town while another was killed at Makum when miscreants set ablaze a liquor bottling plant on Tuesday.

In another incident on Tuesday night, two armed ULFA militants came on a motor-cycle to a highway dhaba at Baxirhat under lower Assam's Dhubri district and opened indiscriminate fire on truck drivers killing four Bihar truck drivers and injuring seven.

Reports were also pouring in about clusters of huts belonging to Biharis in different parts of the state being torched, their shops looted, physically assaulted and petty amounts of money extorted from them.

In the busy commercial town of Tinsukia, a large group of angry Bihari people pelted stones on the students of Senairam Higher Secondary School on Tuesday leading to a clash between the mob and the students.