Afghanistan's run-off election will be held on November 7 as scheduled despite the withdrawal of President Hamid Karzai's only challenger Abdullah Abdullah from the contest, the election commission said on Sunday.

Afghan President's top challenger Abdullah Abdullah announced Sunday that he would not participate in the run-off presidential election set on Nov. 7.

"It is unnecessary to participate in an election full of fraud," Abdullah told his supporters in a gathering in Kabul. "I made this decision for larger interest of the country and for strengthening democracy in the country."

"This is a very tough decision," Abdullah said. "I took in a lot of consultation with our people before I made the decision."

According to the constitution, it is possible for the run-off to be held with only one candidate, but that is believed to undermine the government's legitimacy.