Scores of politicians from an influential Pakistani political party have resigned in protest against alleged "repression" of their activists.

Scores of politicians from an influential Pakistani political party have resigned in protest against alleged "repression" of their activists.

More than 80 lawmakers from Pakistan's controversial fourth-largest party, the Muttehida Quami Movement (MQM), quit their roles in parliament, the senate and southern Sindh province's state assembly on Wednesday, accusing security forces of a "one-sided" operation against their activists.

“We have resigned from all three houses in protest against a series of injustices and repression against MQM’s workers and supporters in Karachi,” Dr. Farooq Sattar, the party’s parliamentary leader, told reporters outside parliament.

“We are being sidelined [by security forces] to give space to our political rivals in Karachi,” he claimed.

A security crackdown against militants and gangs in the commercial capital Karachi has also affected MQM, with its party offices being raided earlier this year.

Party chief Altaf Hussein, who lives in exile in London but still delivers fiery speeches by phone, has accused the military of targeting his party after hundreds of activists were arrested for alleged involvement in the targeted killings of political opponents and security forces, extortion and other crimes.

Karachi-based MQM initially claimed to represent the Urdu-speaking migrants who moved to Pakistan with the partition of India in 1947 and has strong influence in southern Sindh province but has been accused of operating like an organized gang through its alleged use of violence and intimidation.

The security crackdown in Karachi has seen more than 300 suspected drug traffickers and 200 suspected Taliban fighters killed in clashes with security forces in Karachi over the last ten months, though local media have speculated over whether some of the deaths were extra-judicial killing.