The violence is spreading insecurity which has hampered relief work, aid groups said.

Unrest had spread to once stable areas and welfare agencies were forced to scale back aid delivery even as drought and food price hikes put millions of people in difficulty, the Agency Coordinating Body for Afghan Relief (Acbar) said on Friday.

"So far this year the number of insurgent attacks, bombings and other violent incidents is up by approximately 50 per cent on the same period last year," said Acbar, a grouping of about 100 Afghan and international non-governmental organisations.

There were 463 Taliban attacks in May and 569 in June, it said in a statement, citing figures from a range of sources including the Afghanistan NGO Safety Office.

This was "greater than the number of such attacks in any other month since the end of major hostilities following the international intervention in 2001," it said.

"This year 2,500 people have reportedly lost their lives in the conflict and whilst exact figures are not yet available, this could include up to 1,000 civilians," the group added.

Initial estimates were that more than 260 civilians were killed in July, which has higher than any other month in the past six years, it said.

July saw some of the worst violence of an insurgency by Islamic fighters launched after the Taliban were ousted from government in a US-led invasion in late 2001.

A suicide bomb at the Indian embassy in Kabul killed around 60 people and other attacks left dozens more dead.

Military action, mostly air strikes on the Taliban, killed nearly 80 civilians, according to Afghan and military officials.

Acbar said two-thirds of reported civilian casualties could be attributed to insurgent activities especially suicide bombings and the use of civilian property to launch attacks.

But the growing number of air strikes by international military forces, up by about 40 per cent on last year, had also contributed.

In addition, "Aid organisations and their staff have been subject to increasing attacks, threats and intimidation, by both insurgent and criminal groups," ACBAR said.

"This year there have been over 84 such incidents, including 21 in June, more than in any other month in the last six years.

"So far this year 19 NGO staff have been killed, which already exceeds the total number of NGO workers killed last year."

Violence had forced the closure of schools and health facilities in the south, it said. It was also hindering vital development projects.

Drought and higher food prices meanwhile put more than four million Afghans in "extremely difficult circumstances", especially young children and breastfeeding or pregnant woman.

"Increasing and spreading insecurity is jeopardising the delivery of essential humanitarian assistance to these people and threatening their lives and livelihoods," said Acbar.

Acbar called on all parties to the conflict to prioritise the safety of civilians and observe "fundamental standards of humanity" and "the established international laws of armed conflict."

This included distinguishing between civilians and combatants; never using civilians as a shield; not attacking humanitarian, development and medical personnel or supplies.

Acbar also called for an end to hostage taking and said military raids should be conducted with proportionate force, with speedy compensation for civilians who suffered as a result.