A record number civilians were killed in Afghanistan's decade-long war last year, with a dramatic rise in the number of deaths from suicide attacks, according to the United Nations.

A total of 3,021 civilians died -- mostly at the hands of insurgents -- up eight percent from 2,790 in 2010, the United Nations Assistance Mission in Afghanistan (UNAMA) said in its annual report, released on Saturday.

It was the fifth straight year that the toll has risen, with a total of 11,864 civilian lives claimed by the conflict since 2007.

The report stands in contrast to an upbeat assessment of 2011 as "remarkably successful" by NATO-led forces, who are preparing to withdraw combat troops in 2014 and hand security over to the Afghan government.

The UN has disagreed previously with NATO assessments, saying in September that the number of security incidents was up 39 percent in the first eight months of the year, while NATO said they were down two percent.

The latest UN report also says the conflict caused growing disruption of life for ordinary Afghans last year, with an estimated 185,632 people displaced -- an increase of 45 percent over 2010.

Taliban-led insurgents caused 77 percent of the deaths last year, up 14 percent from 2010, while NATO-led and Afghan government forces were responsible for killing 410 civilians -- 14 percent of the total, the report said.

Another 279 deaths -- nine percent -- could not be attributed to either side.

The record loss of life was blamed mainly on changes in the insurgents' tactics, which saw an increased use of homemade bombs and deadlier suicide attacks.

Most deaths attributed to NATO forces were a result of attacks from the air, but there was an overall decline of four percent in the number of civilians killed by pro-government forces, the report said.

Controversial night raids targeting Taliban leaders were responsible for 63 civilian deaths, down 22 percent from the previous year.

Overall, "Afghan children, women and men continue to be killed in this war in ever-increasing numbers," said UN special representative Jan Kubis.

"For much too long Afghan civilians have paid the highest price of war. Parties to the conflict must greatly increase their efforts to protect civilians to prevent yet another increase in civilian deaths and injuries in 2012."

Improvised explosive devices (IEDs) were the single largest killer of Afghan civilians in 2011, taking the lives of 967 people, the report said.

The insurgents had increased their use of "illegal, indiscriminate victim-activated pressure plate IEDs" that can be detonated even by children stepping on them, the report said.

The civilian death toll from suicide attacks in Afghanistan "rose dramatically" in 2011 to 450 -- an increase of 80 percent over 2010.

"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."

The geographic distribution of civilian casualties shifted significantly, particularly in the second half of 2011, as the conflict lessened in intensity in the south and intensified in the southeast, east and north.

The UN report urges the 130,000-strong NATO force to review its tactics aimed at preventing civilian loss of life in all military operations -- "in particular aerial attacks".

It also calls for stronger efforts to prevent civilian casualties in the night raids, which have been widely condemned, including by Afghan President Hamid Karzai.

[Photo credit: Lizette Potgieter / Shutterstock.com.]