A senior NATO commander says that 80 percent of Afghanistan is free of violence but warned an insurgency still rages in the south and east, fuelled by fighters coming from neighbouring Pakistan.

"About 80 percent of Afghan territory and the Afghan population is not affected by security problems or violence," Lieutenant General Olivier de Bavinchove told AFP in an interview.

"On the other hand, there is a huge contrast when it comes to security between the different regions and districts," said Bavinchove, Chief of Staff of NATO's International Security Assistance Force (ISAF).

His claims contrast sharply with United Nations numbers showing that August was the second deadliest month in five years for Afghan civilians, with a total of 374 -- more than 10 a day -- killed and 581 injured.

Despite that the head of French forces in the country said that the north and west are peaceful, with signs of development and improved governance, and sparsely populated central Afghanistan is almost entirely safe, he said.

"Then we have the frontier zones in the east and south of the country, where an insurrection is quite active, very localised most of the time, but which is supported by fighters coming mainly from Pakistan," he added.

"ISAF's efforts are today particularly focused on these areas."

Kabul accuses Pakistan of failing to stop fighters crossing into Afghanistan from its lawless border areas to support the Taliban, while Islamabad complains Pakistani Taliban are using havens in Afghanistan.

Bavinchove meanwhile conceded that insider attacks, also known as green-on-blue attacks, had "really complicated our work. They have undermined the trust that must exist between Afghan and coalition units".

He estimated that only 25 to 35 percent of insider attacks were planned by the Taliban and said the rest were down to a lack of education and a society where violence is commonplace.

"For centuries, Afghans have been used to settling conflicts with violence, including domestic conflicts," he said in the interview on Saturday.

The death of a NATO soldier in a suspected insider attack in eastern Afghanistan on Saturday took the number of ISAF troops killed in such incidents to 52 this year.

Bavinchove said that France's troop withdrawal plans -- it has nearly 3,000 soldiers in the country -- were going forward "exactly as planned".

France has brought forward the date for its pullout so it will be completed by the end of this year -- 12 months earlier than Paris initially planned and two years before the NATO deadline for the vast majority of its troops.