Villagers told Gilani the kidnappers drove off in the campaigners' two vehicles, the Associated Press (AP) news agency reported.

Nisar Ahmad Popal, the local district chief, told the AP that it was not clear if the kidnappers were members of the Taliban or political rivals of Gilani.

Elections for the Wolesi Jirga, Afghanistan's lower house of parliament, are scheduled for September 18. But security concerns recently led the government to decideit would not open more than 900 polling stations, around 15 per cent of the total, for the vote.

Surge in violence

Most of the closed stations are located in Afghanistan's east and south; the south in particular has seen a surge of violence in recent months.

More than 2,500 candidates are competing for 249 seats in what will be Afghanistan's second parliamentary election since the US-led invasion in 2001.

In 2005, when the first elections were held, 328 women registered to run; that number has risen to 406, according to the Guardian newspaper.In the Wolesi Jirga, 64 seats are reserved by law for women.

But the Taliban and other conservative groups have routinely threatened female politicians, educators and students.

According to the Free and Fair Election Foundation of Afghanistan, female candidates have been "inundated" with threatening phone calls from insurgents, political rivals and ordinary citizens, the Guardian wrote.

Policemen killed

Earlier on Thursday, a group of at least 10 armed men launched a pre-dawn attack on a police checkpoint in the northern city of Kunduz, killing eight policemen and wounding another.

A Taliban spokesman claimed responsibility for the attack.

The assailants hoped to steal the policemen's weapons, but two or three were wounded and the group was beaten back, Abdul Raziq Yaqoubi, the provincial police chief, told the Associated Press news agency.

Mohammad Omar, the governor of Kunduz, said the policemen were asleep at the time of the attack and that only one escaped unharmed.

Yaqoubi claimed the assailants came from Russia's Chechnya province, though no other details on the attackers were available.

Some analysts, sceptical of the scant available evidence to prove the claim, have expressed doubtthat Muslim Chechen fighters have joined up with the Taliban in any significant numbers. But Nato has claimedthat Chechens - along with Uzbeks, Arabs, Pakistani and other "foreign fighters" - are present in Afghanistan.