Voters queued up at polling stations across Pakistan on Thursday to elect councilors and mayors in the second phase of municipal elections.

There were reports of sporadic violence and at least six people were dead and dozens injured, police officials said.

This happened despite deployment of thousands of soldiers, paramilitary troops and a large number of police at polling stations. In the first phase of the elections on August 18, 22 people were killed and more than 200 injured.

All the deaths were reported from the eastern Punjab province, where two people died during clashes outside a polling station in the eastern town of Jhang, area police chief Hamid Mukhtar Gondal said.

Gondal said police arrested three election officials for allegedly supporting a candidate and trying to rig the polls.

Police arrested 20 people in the eastern city of Lahore [Images] for 'disturbing peace and carrying weapons', said Tariq Salim, the city police chief.

Voting began in 54 districts of Pakistan amid tight security, said Kanwar Mohammed Dilshad, a senior election official.

Elections for councilors and mayors are held every four years in the predominantly Islamic nation, where municipal officials look after the welfare of communities, including supervision of schools, clinics and roads.

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Under election laws, no political or religious groups are allowed to field candidates. However, many running for municipal office have behind-the-scene backing from both opposition groups, as well as the ruling Pakistan Muslim League (Quaid-e-Azam) party.