BRUSSELS - Poor communications between NATO troops and Afghan authorities led to the death of several civilians during an alliance operation against the Taliban in October, NATO officials said.

NATO officials have said about 30 civilians were killed in the incident in the Panjwaii district of southern Kandahar province; Afghan officials have put the figure has high as 80.

A report on the incident, which followed a joint Afghan-NATO investigation, was presented to 26 NATO ambassadors Wednesday.

"The main conclusion of the report is that this tragic event took place primarily because communications between international forces and local authorities did not work well enough,'' NATO spokesman James Appathurai said.

But he said the report would not be made public and he would not give details, saying disclosure could reveal sensitive information about the operations of the 32,000-strong NATO force in Afghanistan.

NATO's International Security Assistance Force already has made improvements to the way it works with Afghan local authorities, he said.

Appathurai also expressed concern over an announcement last month by Pakistan that it is considering planting landmines at sections of its border with Afghanistan to stop insurgents from crossing the frontier.

"NATO is looking carefully at this issue but I would say with deep concern and strong reservations,'' he said, adding the alliance hopes to discuss it soon at high-level meeting with Pakistani and Afghan officials.

All NATO countries, apart from the United States, have signed the Ottawa Treaty, which bans the planting of landmines.

ISAF has acknowledged NATO troops killed too many civilians during fighting last year against the resurgent Taliban militants. The deaths have prompted Afghan President Hamid Karzai to appeal for foreign forces to use maximum caution.

"The single thing that we have done wrong and we are striving extremely hard to improve on (in 2007), is killing innocent civilians,'' Brig. Richard Nugee, ISAF's chief spokesman, told a news conference in Kabul last week.

NATO officials said Taliban attacks kill far more civilians but it is concerned fatalities caused by international forces are boosting support for the insurgents.

"NATO takes every step to prevent civilian casualties,'' Appathurai said.

Most of the victims in the October incident were nomads who had wandered into fields where international forces and Afghan army units were seeking to hunt down "significant numbers'' of Taliban militants, Appathurai said.

"This was a highly complex, fast-moving operation,'' he said, adding the report showed NATO troops failed to co-ordinate with local authorities who were aware the nomads were in the line of fire.