LONDON, August 14, 2008 (AFP) - Recent deadly attacks in and around Kabul show that Taliban insurgents are closing in on the Afghan capital, seven years after they were ousted from power, a think-tank said Thursday.

Three female aid workers were killed Wednesday near Kabul, in the deadliest such attack in years involving international aid staff, an attack claimed by the Taliban.

The Senlis Council warned last November that Afghanistan was 'in crisis' and at risk of becoming a divided state, since the Taliban had a permanent presence in more than half -- 54 percent -- of Afghan territory.

THis was 'a statistic that has clearly worsened over the course of 2008,' it said Thursday, noting that it had warned a few months ago that the Taliban was moving in on Kabul.

'Recent news reports ... provide further evidence to back up the findings,' said the council, an international independent security and development policy group.

The group said its own recent research showed that more than half of Wardak province -- neighbouring Logar province, some 45 minutes from Kabul by road -- was now under Taliban control.

This research 'is proof of the Taliban's resurgence in and around the capital, as well as in their southern and eastern heartlands,' it said.

On Wednesday the International Rescue Committee (IRC) aid group suspended its activities after three of its international workers and their Afghan driver were killed when gunmen shot repeatedly at their vehicle.

Also this week a British soldier and four civilians were killed after a suicide attacker drove a car bomb into a patrol of NATO-led forces on a busy road in Kabul on Monday. The bombing was also claimed by the Taliban.

On Thursday three US-led coalition soldiers were killed in an explosion in southern Afghanistan, taking to 17 the number of international troops to die in the country this month.

The deaths also took to 161 the number of international troops killed in Afghanistan this year, most of them in attacks in the south of the country, notably bombings.

Taliban fighters launched an insurgency soon after being ousted from government in late 2001 by a US-led coalition after the September 11 attacks in New York and Washington.