Kabul  - Afghanistan's infrastructure is weak and partially destroyed. Literacy rates in the country on the Hindu Kush are among the lowest in the world. The country's geography makes many regions almost impassable, and it is racked by a Taliban insurgency, in particular in the southern and eastern provinces.

All those factors create difficult circumstances for holding the presidential election on August 20, the second free presidential polls in the country's history.

UN special envoy Kai Eide said the Afghan polls were the "most complex and challenging elections I have ever witnessed."

Thirty-seven candidates, among them two women, are competing. Four of the original 41 candidates have withdrawn from the race.

Incumbent Hamid Karzai, 52, is widely expected to come out on top.

Elections are also to take place for the councils of Afghanistan's 34 provinces.

According to estimates, about 17 million of Afghanistan's 30 million people have registered to vote. About 12.5 million were already registered for the first presidential elections in 2004. Another 4.5 million registered in recent months.

Voter registration proceeded surprisingly peacefully despite Taliban threats.

The militants called for a boycott of the polls and announced roadblocks for the day before the elections.

About 100,000 foreign soldiers from 42 nations - about two-thirds of them from the United States - as well as 200,000 Afghan solders and police are due to protect the election proceedings.

Voters can cast their ballots in 29,000 polling stations. Stations located in remote mountainous regions are to be provided with voting materials transported on more than 3,100 donkeys.

Ballot counting is to begin on August 21, the day after the elections, which is also the start of the holy Muslim month of Ramadan.

The Independent Election Commission expected preliminary results by September 3 and final results for both the presidential and provincial council elections by September 17.

Should none of the candidate receive an absolute majority in the first round, a presidential runoff was scheduled for the first week in October, in which the top two vote-getters would compete. (dpa)