Afghan presidential election campaign begins

The campaign for Afghanistan's presidential election has been formally launched, with rallies for key candidates in the capital, Kabul.

The election is scheduled to take place on 5 April, with 11 candidates to replace Hamid Karzai, who cannot stand again.

Security is the major issue, with the Taliban threatening to target the campaign. Two workers for candidate Abdullah Abdullah were shot dead in the western city of Herat on Saturday.

David Loyn reports from Kabul.