KANDAHAR: The Taliban on Sunday threatened for the first time to attack Afghan polling stations, escalating their bid to derail key elections this week after striking NATO in the heart of Kabul.

The threat was made in leaflets, pinned up and dropped in villages in the south, and authenticated by a Taliban spokesman who said the militia would accelerate its bloody campaign of violence on the eve of polls.

Afghanistan's electorate of 17 million are to vote Thursday to elect a president for only the second time and 420 provincial councillors in a massive operation clouded by insecurity and logistic headaches.

"This is to inform respected residents that you must not participate in the elections so as not to become a victim of our operations, because we will use new tactics," said one leaflet distributed in Kandahar city and seen by AFP.

The letter was written by Mullah Ghulam Haidar, the guerrillas' purported operations commander in Kandahar city. It said voters -- as allies of the Afghan government and foreign forces -- would be considered enemies of Islam.

"All people are being informed that you must not rent out property to voting centres and if anyone did -- even after elections -- they may face problems," said the letter.

Taliban spokesman Qari Yousuf Ahmadi confirmed the leaflets were authentic and that commanders were ordering the masses to boycott the vote.

"We are using new tactics targeting election centres... We will accelerate our activities on election day and the day before," the spokesman told AFP.

"I cannot comment on the new tactics we will use. Targeting polling stations won't just be in the south, it is for the whole country," he added.

The leaflets marked the first direct Taliban threat to attack polling sites. Late last month, the Taliban ordered voters to boycott the polls and join the ranks of the militia in waging holy war to "liberate" Afghanistan.

Election officials say insecurity makes polling unlikely in nine out of 365 districts, mostly in the south, while the number of polling stations could be down as much as 12 percent on an original plan for nearly 7,000.

Sunday's Taliban threat flew in the face of an announcement from Karzai's controversial younger brother, Ahmed Wali, that peace deals had been reached with Taliban commanders in the south to ensure safety at the polls.

Agha Jan, a 24-year-old living just outside Kandahar city told AFP he saw the threat letters pinned on all six mosques in his village of Haji Arab, but said nothing would deter him from voting.

Ahmad Jan, a resident of neighbouring Zabul province, he said saw letters in two districts "telling people that polling stations will be targeted and people must avoid going there".

Taliban threats and soaring attacks have raised widespread concern that poor turnout on Thursday could jeopardise the legitimacy of the elections.

A suicide bombing outside NATO headquarters in Kabul on Saturday killed seven civilians and wounded 91 others, underscoring the ability of the Taliban, which claimed the attack, to operate with impunity.

It "was a warning that the Taliban can attack any time," said analyst Waheed Mujda. "The tactics they use make them very difficult to stop," he said.

Thousands of extra US troops have poured into the south, stepping up the fight to crush insurgents but rising attacks have stoked fears that the threat of violence will keep many voters away from the polls.

US and British fatalities have reached new records since the 2001 invasion ousted the Taliban regime and installed a Western-backed administration headed by President Hamid Karzai, who is seeking re-election this week.

The deaths of two British soldiers on Saturday brought to 201 the number of British troops to die during the eight-year war.

The milestone will inevitably arouse renewed discussions in London about the role of Britain -- after the United States the second largest contributor of troops -- their level of equipment and whether any progress is being achieved.

"But my commitment is clear: we must and will make Britain safer by making Afghanistan more stable," said Prime Minister Gordon Brown.