A key powerbroker from northern Afghanistan has tendered his resignation as military adviser to President Hamid Karzai to challenge him in October elections.
General Abdul Rashid Dostum, from Afghanistan's ethnic Uzbek minority group, will stand against Mr Karzai, who is from the country's largest Pashtun tribe.
Afghanistan's election law stipulates that military officials intending to stand for president need to resign before registering their candidacy.
Monday is the last day for registrations and candidates are required to announce the names of their two vice presidents simultaneously.
A presidential official confirmed Gen Dostum's resignation offer today. Mr Akbar Bai said the decision was based on Gen Dostum's belief that Mr Karzai had targeted non-Pashtun groups, suggesting ethnicity could be a major theme in Afghanistan's first free and direct vote.
Gen Dostum announced his candidacy for the race in the key northern city of Mazar-i-Sharif at a gathering on Thursday, the same day he submitted his resignation to Mr Karzai, Mr Bai said.
"Dostum has decided to stand because he is unhappy with Karzai's policies," Mr Bai told Reuters.
He said they included Karzai calling non-Pashtun commanders "warlords" and carrying out an "imbalanced" disarmament drive of factional forces that has mainly affected minority groups in the north and west.