By Subir Bhaumik BBC correspondent in Calcutta

Sunday's village council elections in the Indian state of West Bengal were marred by heavy violence, forcing the authorities to step up security.

It followed an equally violent campaign for the more than 50,000 village seats in the state in which more than 30 people were killed.

"This is easily West Bengal's most violent elections in recent memory and brought back memories of the early 1970s when the state was rocked by massive violence," said Pradip Bose, Bengal's leading political sociologist known for his work on political violence in the state.

We do not ask for imposition of central rule but these polls have been a farce and must be held again Tathagatha Roy BJP state party chief

Thousands died in the 1970s when the state police used questionable methods to quell a violent Maoist uprising.

The worst violence on Sunday was reported from the state's northern district of Murshidabad bordering Bangladesh, where five people died in violent clashes between Communist and Congress supporters.

Five died on Saturday when crude bombs they were making exploded in the district's Domkal village.

Fierce clashes also erupted between the Communists and the supporters of a small socialist party, the Socialist Unity Centre of India, at Kultoli in the Sundarbans delta south of Calcutta.

At least five died in gunfights and locally made crude bombs were freely used.

Similar clashes were also reported from two areas north of Calcutta - again close to the border with Bangladesh.

The West Bengal Election Commission was flooded with opposition complaints about alleged capture of election booths, false voting and terror unleashed by gun-toting Communist supporters.

But the Communist party chief in West Bengal, Anil Biswas, said their supporters were attacked in most places.

"Take a close look at the sites of violence. They all happened where the opposition is stronger than us and mostly our supporters were targeted.

"But the media highlights the opposition complaints as if law and order has broken down in West Bengal. Nothing could be further from truth," Mr Biswas told a news conference.

High-handedness

But it was not merely the opposition parties that were complaining against Communist high-handedness.

Even the left-wing parties who share power with the Communists in West Bengal for 25 years now were bluntly attacking them.

"They are not sparing our supporters wherever we are strong and the Communists want to run us down. The Communists are running around with guns in one hand and the red flag in the other," said Khiti Goswami, the state secretary of the Revolutionary Socialist Party or the RSP.

This is easily West Bengal's most violent elections in recent memory Pradip Bose leading sociologist

He said the RSP will have to "consider whether they can stay in the Left Front with the Communists" if the violence continued.

Mr Goswami had reasons to be upset.

For the second time in 10 days, the state's Public Works Minister Amar Choudhury of RSP was attacked by Communist supporters in the southern town of Canning in the Sundarbans delta.

Turnout, however, remained high in most areas other than those affected by violence - between 70-80% on average.

But the chairperson of the opposition Trinamul Congress party, Mamata Banerji, alleged that the Communists had "stuffed ballot boxes with false votes and reduced the elections to a farce".

The party has threatened to boycott the state assembly in protest against the "farcical polls".

The State Election Commissioner Ajoy Sinha did not agree.

"The polls were by and large peaceful but wherever we have received definite complaints of intimidation and false voting, we have ordered fresh polls," he said.

The BJP's state party chief Tathagatha Roy demanded that the polls be fully cancelled and held all over again.

"We do not ask for imposition of central rule but these polls have been a farce and must be held again," he said.

During the 25 years of Communist rule, the village councils have been progressively empowered.

But the opposition alleges they use violence and terror to control these councils which are believed to be the bedrock of Communist victories in successive assembly and parliament elections in West Bengal.