Gunmen on a motorcycle have shot and killed a senior member of Imran Khan’s Pakistan Tehreek-e-Insaf party.

Zohra Shahid, 59, was gunned down outside her home in the city of Karachi in southern Sindh province.

She was the vice-president of the PTI party formed by Mr Khan, the former Pakistani cricket star, who is also chancellor of the University of Bradford.

No-one has claimed responsibility for the killing which comes as Karachi votes in a partial re-run of Pakistan’s general election.

Police are investigating whether Mrs Hussain’s killing was the result of an attempted robbery or a politically-motivated murder.

Tensions are running high between PTI and Karachi’s dominant MQM party after Mr Khan’s party accused the MQM of widespread vote rigging.

On his Twitter feed, Mr Khan called for a country-wide protest at the killing of his deputy.