Kabul police chief Zahir Zahir resigned yesterday after three Taliban attacks in 10 days on foreign guest-houses in the capital, while officials said Afghan forces had ousted insurgents who tried to seize the former US and British base Camp Bastion in the south.

Taliban fighters breached the perimeter of Camp Bastion in Helmand three days ago, just a month after the base was handed over to the Afghan army.

The attacks of recent days have renewed fears that Afghanistan's army and police cannot secure the country.

The charity whose Kabul guest house was targeted in the latest such assault on Saturday, US-based Partnership in Academics and Development (PAD), said three people were killed by insurgents who used guns and explosives.

They were identified as a South African father and his two teenage children by a colleague of the mother, who survived the attack.

Kabul's police spokesman declined to comment on the reason for the chief's resignation. "We can only confirm he will not continue his job as police chief anymore," Hashmat Stanekzai said.

Violence across Afghanistan has surged this year as the Taliban and their allies have stepped up their activities ahead of the scheduled withdrawal of most international troops by the end of next month.

Over the past 10 days, three compounds used by foreign ­organisations have been hit by armed attackers.

In separate attacks in Kabul, two American soldiers, two British embassy workers and dozens of Afghan civilians have died.

The Taliban said they had attacked the foreign guesthouse because they believed it to be a Christian centre.

This was the second time this year that the Taliban has targeted a group that it believed had links to Christianity.

PAD, which supports education in Afghanistan, could not be reached immediately for comment.

The South African victims were members of a devout Christian family who had lived in Afghanistan for nearly 12 years, with the father running the charity and the mother working as a doctor, said a colleague at the Kabul clinic where the mother worked.

The 17-year-old son had been applying to universities in the United States. His sister was 14, said the colleague, who asked not to be identified for security reasons.

At the former Camp Bastion, Afghan soldiers finally ousted a group of Taliban from the base.

Fighting had ended yesterday and troops were clearing the area that had been seized by a few dozen insurgents, said Omar Zwak, a spokesman for the Helmand governor.

Further north in Helmand's Sangin district, a smaller army post was attacked and 12 soldiers killed in fighting on Friday and Saturday, Zwak said.

The Taliban have stepped up attacks in Afghanistan as most foreign combat troops prepare to leave the country. As part of the agreement on the withdrawal of foreign fighting troops, 12,000 Nato soldiers will remain from January 1 to train and advise Afghan security forces.