Afghan aid worker Gayle Williams. Photo: Serve Afghanistan

KABUL, AFGHANISTAN (ANS) -- A woman working for a UK-registered charity has been shot dead near Kabul University in the Afghan capital. Gayle Williams, 34, was a UK and South African national. She was killed by two men on a motorbike, witnesses told the British Broadcasting Corporation (BBC). According to the BBC, the Taliban are reported to have said they killed her because she was working for a Christian organization called Serve Afghanistan.

The BBC said that in August the Taliban killed three foreign women near Kabul.

Police said Ms Williams was killed while walking to work.

An eyewitness told the BBC that two men on a motorbike drew alongside her. One man then got off the motorbike and shot her six times at close range before jumping back on the bike and escaping. Children on the street going to school also saw the incident.

"Some bullets hit her body and some hit her leg and when police got there she was dead," interior ministry spokesman Zemarai Bashary told the AFP news agency, the BBC said.

The BBC's Martin Patience in Kabul says this is not the first time that a foreigner has been killed in the Afghan capital by armed men. But the incident will raise further concerns about the security situation in Afghanistan, our correspondent says.

In the past week, there have been three assassinations in the southern city of Kandahar, all carried out by men on motorbikes.

Serve Afghanistan is a UK registered charity whose overseas staff are volunteers. It focuses on education and training for people with disabilities.

The charity's chairman, Mike Lyth, said the staff and volunteers were in shock over the killing.

He said: "She had been there for about two-and-a-half-years and was managing a community development project focused on disabled people.

"We are deeply saddened about what has happened. She was absolutely lovely and was full of life. A sportswoman and mountaineer -- she just loved that sort of thing. The thought of Afghanistan must have seemed an adventure for her."

The BBC reported that Ms Williams was brought up in South Africa but spent several years living in the UK.

She qualified as a fitness instructor and spent some time in London looking after children with severe special needs before deciding to volunteer in Afghanistan. She was based in Kandahar but returned to Kabul when the situation there became too dangerous.

Taliban spokesman Zabiullah Mujahid told AFP that they killed Ms Williams "because she was working for an organization which was preaching Christianity in Afghanistan."

Mr Lyth believed more attacks were imminent and said: "It is happening increasingly often in countries like Afghanistan. It is a policy of the Taliban to destabilize and knock the government by knocking out all of the aid and NGOs working there."

Lyth said Ms Williams's fellow volunteers needed to discuss their next course of action.

Colleague Rina van der Ende said the news was still difficult to comprehend, the BBC reported.

Van de Ende said: "It still feels unreal that Gayle is not here. She was a very cheerful lady who was always eager to help and we were happy to have her at meetings.

"She was walking to the office. She had to pick up some papers because she had to give training to the Afghan staff about how to work with people with disabilities."

Ms Williams' Kabul-based colleagues also released a joint statement, calling her an "inspiring" person who "put others before herself."

The British secretary of state for international development, Douglas Alexander, called the killing a "callous and cowardly act. To present her killing as a religious act is as despicable as it is absurd -- it was cold blooded murder."

Ms Williams leaves behind her mother in the UK and a sister in South Africa.

The BBC explained that this year 29 aid workers have been killed in Afghanistan; five of whom were international staff.

In August another aid group, the International Rescue Committee, suspended operations after three of its foreign female staff -- a British-Canadian, a Canadian and a Trinidadian-American -- were shot with their Afghan driver close to Kabul.

The BBC said the Taliban claimed responsibility for that attack, saying the women were foreign spies.