Imran Khan has suffered a head injury after falling 5m from a platform lift as it carried him on to a stage for an election rally.

Gunmen have killed the lead Pakistani prosecutor in two high-profile cases shocking a country reeling from Taliban attacks as it prepares for nationwide elections.

Christian communities across Pakistan have launched angry protests after a Muslim mob set fire to a Christian neighbourhood in Lahore.

Under police guard, thousands of health workers pressed on with a polio immunisation program after nine were killed elsewhere in Pakistan by suspected militants who oppose the vaccination campaign.

Report highlights increasing use of 'double-tap' tactics which are terrorising an entire population with death from the skies.