Ahmad Wali Karzai, the younger brother of President Hamid Karzai, told AFP that talks with insurgent leaders in the troubled south of the country were aimed at ensuring as many voters as possible could cast their ballot.

"Discussions with some of the Taliban groups and their commanders have begun at the community level in a bid to persuade them to not create any problem on (voting) day," Karzai said.

"This has happened in some areas but there has not been any agreement signed with the Taliban," said Karzai, who heads the Kandahar provincial council, an elected body, and runs his brother's campaign in the violence-plagued region.

An escalating insurgency in the country's south, and Taliban threats to prevent people from reaching polling stations has stirred concerns that voter turnout could be low, thus compromising the legitimacy of the results.

The presidential vote and parallel elections for provincial councils, is set for 20 August.

The incumbent is running for a second term and analysts say he needs to shore up his ethnic Pashtun powerbase in the southern provinces, which have seen the worst of the Taliban violence.

Karzai refused to give further details.

Taliban leaders have repeatedly dismissed any likelihood of entering into talks with Karzai's Western-backed government until all US and NATO-led foreign forces withdraw from the country.

"We have not talked to anyone," Yousuf Ahmadi, a Taliban spokesman, told AFP by telephone from an undisclosed location.

"Neither our local commanders nor our leadership have spoken to anyone and will not do so," he said.