By Andrew North
BBC correspondent in Kabul
Afghanistan's powerful defence minister, Mohammed Fahim, has confirmed he is backing former education chief, Yunus Qanuni, for the presidency.
Fahim (L), is backing Northern Alliance colleague, Qanuni (R)
In a rare media appearance, Mr Fahim, leader of the Northern Alliance, said interim President Hamid Karzai had abandoned his group.
Mr Karzai last week decided to choose Ahmed Zia Massoud as his running mate over Mr Fahim.
The interim leader is the favourite to win on 9 October.
Mr Fahim's Northern Alliance mujahideen had helped overthrow the Taleban in 2001 with US support and he was initially seen as a potential running mate for Mr Karzai.
The interim leader's decision not to choose him as vice-presidential candidate was welcomed in many quarters.
But as the defence minister still controls a significant armed force of his own, some Afghans feared a violent response.
International peacekeepers in Kabul were put on heightened alert.
However, Mr Fahim said on Wednesday he was committed to what he called peaceful political competition.
He criticised those who had called him a warlord and had predicted a military response from him.
Now is no longer the time for the gun, he said.
Mr Fahim said he had told President Karzai that not supporting his Northern Alliance faction was a mistake.
That left him no choice, he said, but to back the presidential bid of Mr Qanuni, another leading Northern Alliance figure.
Mr Karzai's running mate - Mr Massoud - is also linked to the alliance.
He is brother of the group's late leader, Ahmed Shah Massoud.