Media playback is unsupported on your device Media caption Civilian casualties have fallen, although Afghans are not celebrating, as Karen Allen reports

Civilian casualties in Afghanistan have fallen for the first time in five years, the latest UN figures show.

Those killed or injured fell by 15% in the first half of 2012 compared with the same period last year.

Analysts say increased sensitivity on both sides about the impact of civilian deaths in Afghanistan has led to more carefully targeted attacks.

In the latest violence, Nato says three of its soldiers were killed in a militant attack in Kunar province.

Local officials in the provincial capital, Asadabad, told the BBC two suicide bombers targeted US troops near the governor's compound in the city.

Nato soldiers were walking from their base at the time of the attack, police told the AFP news agency.

Hospital officials say a civilian was also killed.

The Taliban have said they carried out the attack. Nato has not yet revealed the nationalities of those who died.

'High level'

"In the first six months of 2012, the armed conflict in Afghanistan continued to take a devastating toll on civilians," the United Nations Assistance Mission in Afghanistan (Unama) report said.

Analysis Civilian casualties have risen steeply every year for the past five years - until this one. The numbers are still high. More than 1,100 people were killed or injured in the first six months of the year - far more than three or four years ago. Almost a third of the casualties were women and children. And it may also be premature to talk about a new trend. But the fact the numbers have fallen at all is significant and begs the question: Why? Taliban attacks against Nato-led forces have actually increased in recent months so it is not simply about the level of violence. But both sides, pro- and anti-government, have become increasingly sensitive in the past few years about the impact of civilian casualties on public opinion. In the broader battle for hearts and minds, it is a key factor. That awareness has caused shifts in tactics. The Taliban are trying to make their attacks more targeted, focusing more on checkposts and military bases and less on markets and public gatherings.

"Between 1 January and 30 June 2012, conflict-related violence resulted in 3,099 civilian casualties or 1,145 civilians killed and 1,954 others injured, a 15% decrease in overall civilian casualties compared with the same period in 2011," it said.

The report emphasises however that while the reduction of civilian casualties "reverses the trend in which civilian casualties had increased steadily over the previous five years", Unama remains concerned that the number of civilian deaths and injuries "remains at a high level".

The decrease contrasts with Nato figures that show Taliban attacks between April and June this year were 11% higher than the same quarter in 2011. A record 3,021 civilians died throughout last year, 1,510 of them in the first six months, according to the UN.

The figures show that there was a "notable increase" in enemy initiated attacks (EIAs) in May and June, coinciding with the early end this year of the poppy harvesting season, which is traditionally a time when insurgents become more active.

The Unama report also highlighted a 53% rise in targeted killings in the first six months of 2012 - mostly of politicians - by "anti-government elements". It said that over that time, 255 civilians were killed and 101 wounded, compared with 190 deaths and 43 injuries during the same period in 2011.

The BBC's Bilal Sarwary in Kabul says that this tactic has become a weapon of choice for the militants, creating the fear and intimidation among civilians that is essential to keep the insurgency alive.

Both Nato and the UN agree that improvised explosive devices (IEDs) remain the leading cause of conflict-related deaths of women and children.

The BBC's Jill McGivering says that the growing use of roadside bombs may be intended to target passing troops but often kill families instead.

Only about 10% of civilian casualties are caused by pro-government forces, the UN says.

But our correspondent says that most of these relate to Nato air strikes when the nature of casualties - militant or civilian - is often disputed.

The findings come as about 130,000 Nato troops prepare to withdraw from Afghanistan in the next 18 months.

The Taliban has rejected the UN figures.