The number of Afghan civilians killed in the war torn country rose 25 per cent in the first six months of 2010, despite a reduction in the number of civilian deaths caused by NATO action, a UN report said Tuesday.

The report showed that the Afghan war is getting even more deadly because of insurgent actions against civilians, undermining coalition efforts to improve security in the country.

"The human cost of this conflict is unfortunately rising," Staffan De Mistura, the top UN envoy in Afghanistan, said while releasing the report. "We are very concerned about the future because the human cost is being paid too heavily by civilians. This report is a wake-up call."

According to the report by the Human Rights Unit of the United Nations Assistance Mission in Afghanistan, 1,271 Afghans died and 1,997 were injured, mostly in bombings -- in the first six months of 2010.

In comparison, there were 1,013 civilian deaths in the first six months of 2009.

The UN said insurgents were responsible for 72 per cent of those deaths in 2010, compared to 58 per cent in 2009.

Even though the UN blames insurgents for almost three-quarters of the deaths, the report could undermine the mission as the Afghan public is increasingly blaming the U.S.-led mission for the violence.

De Mistura argues that the Taliban is hurting its long-term goals by killing so many civilians.

"If they want to be part of a future Afghanistan, they cannot do so over the bodies of so many civilians," de Mistura said. "One day, when unavoidably there will be a discussion about the future of the country, will you want to come to that table with thousands of Afghans, civilians, killed along the road?"

Civilian deaths from coalition actions were down 18 per cent in the first half of 2010. Deaths dropped to 223 from 310 in 2009, mostly due to a decrease in air strikes, the report said.

Air bombings accounted for 31 per cent of civilian deaths caused by pro-government forces.

Gen. Stanley McChrystal, the former NATO commander, introduced strict new rules for air strikes, a policy change his successor, Gen. David Petraeus, has continued.

"Every Afghan death diminishes our cause," Petraeus said in a statement

"We know the measure by which our mission will be judged is protecting the population from harm by either side. We will redouble our efforts to prevent insurgents from harming their neighbors."

With files from The Associated Press