KABUL - Afghan civilian deaths dropped 22 per cent in the first six months of 2012 compared with a year ago, largely due to a decrease in the number killed by insurgents' homemade bombs and suicide attacks, the United Nations said in a report released Wednesday.

It was the first time the U.N. data have shown such a sustained reduction in civilian deaths since it started counting in 2007. Even so, U.N. officials cautioned that fighting started to pick up in May and that civilian casualties are already spiking again.

"The drop in civilian casualties is a trend that seems to be hollow, as the percentage drop in civilian casualties has dropped consistently over the last three months as the fighting season has intensified," said James Rodehaver, the head of human rights for the U.N. mission in Afghanistan.

In May, the United Nations said that civilian deaths had dropped 36 per cent in the first four months of 2012 compared with 2011, but did not provide a detailed analysis of the figures and cautioned that much of the reduction was likely due to a particularly harsh winter that decreased fighting overall.

The 22 per cent drop reported Wednesday shows that the positive winter trend has already started to erode.

This spring and summer have been particularly violent, with insurgent attacks up significantly in May and June compared with last year, according to data from NATO forces in the country. June marked the highest number of militant attacks in one month since September 2010, according to the data. The U.N. report did not break out the May-June period in its report.

Overall, 1,145 civilians were killed in Afghanistan between January and June of this year, according to the report. That's down from 1,462 in the first six months of 2011. Injuries to civilians caught up in the crossfire also dropped.

The lower civilian toll this year appeared to be due to a shift by insurgents toward more targeted attacks, hitting Afghan officials or Afghans working with international military forces, and fewer indiscriminate bombings, according to the report. It was unclear if this was because of pressure from international forces or a strategy change on the part of the insurgency.

"Some factors reflect improvements in the security environment while others indicate that anti-government elements may be refocusing their efforts or holding ground in some areas," the report said.

Homemade bombs killed 327 civilians between January and June, down from 444 in the first six months of 2011. Insurgents also killed fewer civilians in suicide bombings that in the year before.

While civilian deaths caused by NATO and Afghan forces have been decreasing for years, this is the first time the U.N. data — the most widely used on the subject — showed a decrease in insurgent-caused casualties.

But even with the reduction, the Taliban and other militants are responsible for the overwhelming majority of civilian deaths in the country. About 77 per cent of the deaths between January and June can be attributed to insurgents, according to the report.

And insurgent-placed homemade bombs continued to be the deadliest weapon for civilians, accounting for 29 per cent of all such deaths in the period.

In the latest such incident on Tuesday, a remote-controlled roadside bomb struck a bus travelling northwest of Kabul, killing at least nine passengers.

Meanwhile, civilian deaths from targeted killings and assassinations increased to 255 from 190 in 2011, the U.N. said. The Taliban have targeted not just officials but also civilians who associate with the Afghan government or the international military. The group has called some of these collaborators and said they do not consider them civilians.

The U.N. stressed that bombings and indiscriminate attacks continue, along with targeting of places frequented by women and children. In one particularly disturbing trend, insurgent attacks against schools increased compared with a year ago.

"Additional measures must be taken to protect civilians and ensure protection of their fundamental human rights," the U.N. said in the report.

News from © The Associated Press, 2012