The first half of this year was the deadliest six months for civilians in Afghanistan since the decade-old war began, the country's UN mission said on Thursday.
Civilian deaths hit a record high, up 15% on the first half of 2010, due to roadside and suicide bombings, increased ground fighting and more deadly air strikes.
The United Nations Assistance Mission in Afghanistan (UNAMA) said 1,462 civilians had been killed in conflict-related incidents. It blamed insurgents for 80% of those deaths up nearly a third on the same period last year.
"The rising tide of violence and bloodshed in the first half of 2011 brought injury and death to Afghan civilians at levels without recorded precedent in the current armed conflict," the report said, adding that plans to hand over security in parts of the country helped fuel the rise in casualties.
"Violence rose as (insurgents) sought to demonstrate that Afghan security forces could not manage security on their own," the report said.
Pro-government forces, including the Afghan police and army and Nato-led troops were responsible for 14% of civilian deaths, a drop of 9%. But air strikes, one of the most controversial tactics in the war, killed more people.
The mid-year report found that air strikes carried out by the Nato-led International Security Assistance Force (ISAF) were the leading the cause of civilian deaths by pro-government forces, so far killing 79 civilians in 2011, up 14%.
Apache attack helicopters played a much more prominent role.
A third of civilian deaths attributed to air strikes in 2010 were caused by those aircraft, while in the first half of 2011 they were responsible for 56% of air strike deaths.
The UN also warned the full picture could be even worse, as the report did not include data from the northern region of Afghanistan between March and June, because the UN office there was closed after it was overrun by a mob that killed seven UN staff.
"It may be that UNAMA is under-reporting civilian casualties given limitations associated with the operating environment," the report said.
Suicide attacks more deadly
While the number of insurgent suicide attacks was largely unchanged, the number of civilians they killed soared 52%, the largest increase in deaths from any tactic.
Insurgents who have been squeezed in some of their traditional heartlands have tried spectacular urban attacks to underline their reach as Nato troops race to prepare Afghan forces for a security handover which begins this year.
"Suicide attacks in 2011 have become more complex, often using multiple bombers in spectacular attacks that kill many Afghan civilians," found the report.
Eight Afghan civilians and one foreigner were killed last month in an assault on Kabul's Intercontinental hotel, just days after a suicide car bomber killed at least 20 people at a hospital in remote east Afghanistan.
There were 190 targeted killings, compared to 181 in the same period of 2010. Ground combat caused more than 304 deaths, up more than a third, with 188 of those deaths attributed to insurgents, 66 to pro-government forces and 50 to crossfire.
Controversial night raids by the US military, which Afghan President Hamid Karzai has criticised as inciting people to join the Taliban-led insurgency, fell slightly in the first half of 2011, accounting for 2% of all civilian deaths.
"However, resentment regarding these raids grew among the Afghan population. Violent demonstrations sometimes followed night raids and led to deaths and injuries of civilians."
The UN mission in Afghanistan also said it was concerned by the increasing use of children in the decade-long war, particularly after recording the youngest suicide bomber, a 12-year-old, who killed three civilians and injured 12 on May 1.