Afghanistan's election campaign kicked off yesterday as the killing of a presidential candidate's aides highlighted the threat surrounding the poll to succeed Hamid Karzai.
Gunmen shot dead two aides of Abdullah Abdullah, a former foreign minister seen as a strong contender, in the western city of Herat on Saturday.
The country is preparing for its first democratic transfer of power. The April 5 election is seen as a key test of the effectiveness of the 350,000-strong Afghan security force as foreign troops prepare to leave.
A dispute between Kabul and Washington over whether a small force stays behind is likely to dominate the campaign.
Karzai has ruled since the fall of the Taliban in 2001, surviving assassination attempts and the treacherous currents of Afghan political life as billions of dollars of military and development aid poured into the country.
He is barred from seeking a third term, leaving an open field, which is likely to trigger a second-round run-off in late May.
Tipped to go through to the run-off is Abdullah, the suave opposition leader who came second to Karzai in the chaotic and fraud-riddled 2009 election.
Among the other heavyweight candidates are former finance minister Ashraf Ghani, Karzai loyalist Zalmai Rassoul and the president's low-profile elder brother, Qayum Karzai.
In comments likely to cause further friction with his Nato allies, Karzai criticised their conduct of the 12-year conflict in an interview with Britain's Sunday Times, in which he described the Taliban as "brothers" and the US as "rivals".
He said "the US-led Nato mission in terms of bringing security has not been successful, particularly in Helmand", a southern stronghold of Taliban militants.
Taliban insurgents have threatened to target the campaign, and the Afghan police and army face a major challenge with little support from Nato troops.