Rampaging tribesmen with bows and arrows and spears massacred more than 100 villagers and burned down 6,500 houses in the remote northeastern Indian state of Assam during the weekend, according to government reports reaching here tonight.

In the worst violence of a turbulent statewide election that already has left more than 90 persons dead, tribal raiders hit 15 villages close to the northern border in midnight raids Saturday, hacking the occupants to death with spears and hatchets before fleeing.

The identity of the attackers was not postively ascertained, but the massacres followed the kidnaping of a tribal candidate in the election in the Chutia District, about 20 miles from the area of the killings, officials reported. Indian news agencies quoted government officials in Tezpur, the district headquarters, as saying the attackers were sympathizers of a tribal political group.

The victims appeared to be Assamese suspected of being linked to a three-year-old, frequently violent ethnic drive to expel nearly a million aliens who have drifted into Assam from neighboring Bangladesh.

Because all of the approach roads and bridges leading to the stricken villages had been destroyed, government officials were unable to reach the scene to verify the death toll, according to Indian news agencies. An official communique from Tezpur said more than 100 had been killed, but sketchy reports from other government agencies in the Assamese capital of Gauhati put the toll as high as 150. The killings reportedly occurred in the Gohpur area of Assam's remote Daurang District.

Some reports from Assam said the massacres may have been motivated in part by recent encroachments by the villagers into the forest areas inhabited by the tribesmen.

Agency reports said police in Gahpur were first attracted to the scene by the glow of houses on fire in the raided villages.

Tribal violence is not uncommon in India's far northeastern states, where foreign correspondents are barred because of ongoing clashes between government forces and armed insurgents of separatist movements. More than 2,000 people were killed in tribal clashes in 1980 in the tiny state of Tripura on Assam's southern boundary.

Most of Assam has been paralyzed by civil disorder for two weeks amid growing demands that Prime Minister Indira Gandhi, who visited the area last week, cancel state elections that were called to end the emergency central government rule imposed last March following disturbances. The phased balloting began today and is scheduled to be resumed Thursday and next Monday. More than 50,000 security forces have been airlifted into the state.

The student-led Assamese movement has been battling to protect the indigent Assamese population's ethnic and cultural identity by striking from the state electoral rolls 4 million immigrants--most of them Moslem and Bengali-speaking refugees from Bangladesh--and expelling nearly a million of them to surrounding Indian states.

Earlier today, 11 persons were reported killed in clashes with police, including three killed when police opened fire on mobs trying to keep voters from ballot boxes. About 100 polling stations could not be opened because of violence, authorities said.