The prime minister of Pakistan, Nawaz Sharif, has warned his party's main coalition partner in Sind province, the MQM, that he'll end their alliance if they don't co-operate fully with investigations into the killing of a respected social reformer.

The dead man, Hakim Mohammad Saeed, was shot last week and Mr Sharif said the evidence so far suggested that MQM militants and one of the party's provincial assembly members Zulfiqar Haider were involved.

He said the MQM had been asked to turn over the accused in the next few days.

The MQM has rejected the accusations as totally false.

Mr Sharif described the violence in Sind as extremely disturbing and said the government was preparing a comprehensive strategy to revamp the police and administration there.