Five Pakistani vaccination workers shot

Five Pakistani polio vaccination workers have been shot dead in the country's largest city Karachi, officials say.

The victims were reportedly working with a UN-backed programme to eradicate polio, which is endemic in Pakistan.

No group has said it carried out the shootings, but the Taliban have issued threats against the polio drive and are active in parts of Karachi.

Aleem Maqbool reports from Islamabad.