Kandahar -- Taliban gunmen on motorbikes gunned down a woman provincial legislator in Afghanistan Sunday as authorities said they had killed 40 more Taliban in their battle to defeat the extremists.

Legislator Sitara Achikzai, a high school teacher and women's rights activist in her 50s, was shot dead outside her home in the volatile southern city of Kandahar, the head of the council, Ahmad Wali Karzai, told AFP.

"She has been martyred by two men on motorbikes and the case is under investigation," said Karzai, brother of President Hamid Karzai.

A spokesman for the insurgent Taliban movement, Yousuf Ahmadi, told AFP by telephone that his militia had carried out the assassination.

Achikzai was targeted because she did not have a "good background," he said, without explaining what this meant.

Achikzai had returned from years of exile in Germany with her husband, a doctor and university lecturer, to work in the city, provincial governor Turyalai Wesa told a press conference, describing her as a "brave woman".

"They left their family, their children and their comfortable life behind in the West and came to Kandahar to live with their people and to serve their people," he said.

The couple had a son and a daughter in Germany, he said.

Provincial police chief Mutaiullah Kate said her single, unarmed bodyguard had said there were four gunmen on two motorbikes.

"Members of the provincial council are allowed five bodyguards each but I don't know why they don't use them," he said.

The Taliban -- who had restrictive policies against women when they were in government between 1996 and 2001, including barring them from work outside of the home -- have carried out similar assassinations in Kandahar.

They admitted to shooting dead the country's most high-profile female police officer in the city last year and are also suspected of the 2006 assassination of head of the provincial women's affairs department.

The fundamentalists were also blamed for an attack in Kandahar in November last year in which acid was sprayed into the faces of schoolgirls.

Afghanistan's provincial councils are elected authorities that act as provincial parliaments and are a key facet of the war-torn country's attempts to install democracy after the ouster of the Taliban government.

Kandahar province, from where the Taliban rose as a militia in the early 1990s, had three women on its provincial council.

One of them, Zarghona Kakar, survived an assassination attempt two years ago in which her husband was killed, an AFP reporter said. A male member of the council was shot dead in 2006.

On April 1 this year, Taliban militants attacked the offices of the Kandahar provincial council on April 1 with four suicide attackers storming the building, some of them opening fire as they went, killing 13 people.

Council elections are due on August 20, coinciding with the presidential vote, and authorities are concerned that the Al-Qaeda-linked Taliban will target the polls.

The NATO-led International Security Assistance Force, which is helping Afghanistan to fight the insurgency and extend government authority, has requested thousands of reinforcements to help shore up security for the vote.

Security forces reported meanwhile Sunday they had killed 40 Taliban militants in separate battles over the weekend.

In one, the rebels ambushed a joint Afghan and foreign forces patrol district of Zabul province late Saturday, sparking an exchange of gunfire that left 22 rebels dead, provincial police chief Abdul Rehman Sarjang told AFP.

Separately, troops killed 18 insurgents in the northeastern province of Kunar late Friday, ISAF said in a statement.

AFP/Expatica