Nominations opened on Monday for Afghanistan's presidential election, with a large field expected to register in the race to succeed Hamid Karzai as the US-led war winds down.
The election next April 5 will mark Afghanistan's first-ever democratic transfer of power as Karzai steps aside after leading the country since the hardline Taliban regime was ousted in 2001.
The presidential race, from which Karzai is barred after serving two terms, is seen as the key test of the effectiveness of 13 years of bloody international military intervention and billions of dollars of aid.
"Around 28 people received the information package for presidential elections," Independent Election Commission (IEC) spokesman Noor Mohammad Noor told reporters as the office opened.
All potential runners must register with the IEC before October 6, and a final list of verified candidates will be published on November 16. No candidate is expected to launch their campaign on Monday.
Presidential hopefuls must be aged at least 40, have a clean criminal record, provide 100,000 voter cards to prove they have a network of supporters and lodge a deposit of one million Afghanis ($18,000).
The tough new criteria were designed "to limit the number of runners", Noor told AFP, after around 40 candidates stood in the chaotic 2009 election that was marred by massive fraud.
Karzai, a charismatic and mercurial figure, has dominated Afghan politics as the country has struggled to develop amid a fierce Taliban insurgency, and there are no obvious front-runners to succeed him.
He has vowed to oversee a free and fair election and said he will not endorse any candidate, but international donor nations have expressed repeated concerns over the vote.
"Credible, inclusive, and transparent presidential and provincial elections in 2014 are now the most important element of Afghanistan's transition," US ambassador James Cunningham wrote in an article in the local media last week.
He called for "broad participation in the elections by men and women from all segments of Afghan society" -- after low participation by women and Pashtuns, the country's largest ethnic group, in the 2009 vote.
Many Afghans fear a surge in violence during campaigning and on polling day, but the government has said its security forces will ensure safety.
Karzai recently said former warlord Abdul Rasul Sayyaf, 2009 runner-up Abdullah Abdullah and former finance minister Ashraf Ghani were possible candidates.
With political manoeuvring well under way in Kabul, attention has now focused on low-profile Foreign Minister Zalmai Rassoul as a technocrat candidate from within Karzai's camp.
Rassoul could put together a broad-based ticket by signing up strongman of the north Atta Mohammad Noor and Mohammad Mohaqiq, a leader of the ethnic Hazara minority, as his vice-presidential candidates.
Other potential runners include Qayum Karzai, the president's brother, and former interior minister Ali Ahmad Jalali.
The election next year coincides with the withdrawal of 87,000 Nato combat troops as Afghan soldiers and police take charge of the battle against the Taliban.