By Daniel Magnowski
KABUL (Reuters) - More than 3,000 civilians were killed in the war in Afghanistan in 2011, the fifth year in a row the number has risen, the United Nations said on Saturday in a report likely to revive tension between the Afghan government and its Western backers.
Civilian deaths undermine support both in Afghanistan and the United States for the U.S.-led war, and are one of the biggest causes of friction between President Hamid Karzai and the NATO-led International Security Assistance Force (ISAF).
Bombs planted on roads, and increasingly deadly suicide attacks that targeted civilians, killed more people than any other type of attack, according to the U.N. Assistance Mission in Afghanistan (UNAMA).
"The tactics of choice of anti-government elements subjected Afghan civilians to death and injury with increasingly lethal results in 2011," UNAMA said in a statement accompanying the report.
"Improvised explosive devices (IEDs) were the single largest killer of Afghan children, women and men in 2011."
Forces fighting Karzai's government and its ISAF allies killed 2,332 civilians in 2011, 14 percent more than in 2010, while security forces battling the militants killed 410 civilians, down four percent from the previous year, UNAMA said.
The number of non-combatants killed last year was 3,021, it said.
Bombs, including roadside mines detonated by people stepping on them or vehicles driving over them, accounted for 967 deaths, UNAMA said, the biggest single killer of civilians.
The "anti-government elements" referred to by the United Nations include the Taliban and allied Haqqani network, among others.
All combatants bore responsibility for civilian deaths, said Jan Kubis, Special Representative for the Secretary-General.
"It's not enough, what's being done," he told reporters. "It is necessary that the parties to the conflict, they do more, they do better, they honor their statements and proclamations."
NATO AIR STRIKES
In November last year, Taliban leader Mullah Mohammad Omar called on his fighters to avoid killing civilians, but only days later, a suicide bomber killed several civilians outside a mosque.
"While the number of suicide attacks did not increase over 2010, the nature of these attacks changed, becoming more complex, sometimes involving multiple bombers, and designed to yield greater numbers of dead and injured civilians," UNAMA said.
"Targeted killings of civilians by anti-government elements also increased in 2011, with UNAMA documenting 495 such killings across the country," it said.
Air strikes launched by the NATO-led force were its biggest killer of civilians, with 187 victims.
Sixty-three people were killed in 2011 in so-called night raids, searches for insurgents usually by U.S.-led forces that have enraged communities and been singled out for criticism by Karzai. That death toll in the raids was down 22 percent from the previous year.
In total, fighting has killed almost 12,000 civilians since 2007, UNAMA said.
"A decade after the war began, the human cost of it is still rising, and that is a tragic and sad thing," Georgette Gagnon, director of human rights for UNAMA, told reporters.
Security is an increasing concern among Afghans as foreign combat troops prepare to leave in 2014.
U.S. Defense Secretary Leon Panetta surprised Kabul this week by saying American troops -- who form the vast majority of the 130,000-strong NATO fighting force -- would stop taking the lead in combat operations before the end of 2013, ahead of a well-publicized end-2014 deadline for the exit for foreign combat forces.
(Additional reporting by Mohammad Aziz; Editing by Rob Taylor and Robert Birsel)