The number of civilians killed or injured in Afghanistan has jumped 31%, despite a fall in the number of casualties caused by Nato-led forces.
More than 1,250 civilians were killed in the first six months of 2010 and another 1,997 civilians were injured, the latest UN six-monthly report shows.
The Taliban and other insurgents were responsible for 76% of the casualties, up from 53% last year.
A spokesman for the Taliban rejected the UN's estimate.
The UN figures for civilian casualties were the worst in nine years of conflict.
According to the UN report, 176 children were killed and 389 injured in the first six months of 2010, up 55% compared with the same period last year.
Most of the casualties were caused by larger and more sophisticated improvised explosive devices (IEDs) used by insurgents throughout the country.
The report noted that the number of civilians executed by insurgents also rose by 95%, especially in the southern part of the country, and included the public executions of children.
Staffan de Mistura, the top UN envoy in Afghanistan, called the report "a wake-up call" for the Taliban.
"If they want to be part of a future Afghanistan, they cannot do so over the bodies of so many civilians," he said of the insurgents.
The UN Assistance Mission in Afghanistan (Unama) called on the Taliban to end their use of IEDs and suicide attacks, and to stop the execution and abduction of citizens.
But a Taliban spokesman, Qari Yusuf Ahmadi, told the BBC's Pashto service that the UN's assessment was inaccurate, accusing the global body of siding with coalition forces.
"This report is far from reality," he said. "The UN's past deeds are obvious to everyone, which are to support the brutal foreign invasion against Afghanistan."
In an attempt to avoid alienating the civilian population, the Taliban has already issued a "code of conduct" that forbids their fighters from seizing weapons and money.
The number of casualties caused by international and Afghan forces fell 30% during the same period to 12% or 386 civilian casualties, the UN figures show.
The decline was driven by a 64% fall in deaths and injuries caused by aerial attacks, which remain the deadliest tactic used by the International Security Assistance Force (Isaf), the UN said.
Afghan President Hamid Karzai has repeatedly warned Western powers that civilian deaths caused by Nato attacks help to fuel the insurgency.
The US and Nato commander in Afghanistan, Gen David Petraeus, said earlier this month: "Every Afghan civilian death diminishes our cause."
Shortly afterwards, a Nato air strike killed up to 25 Afghans travelling to a funeral in Nangarhar province.
In 2009, former Nato commander Gen Stanley McChrystal issued instructions severely limiting the circumstances in which troops could call in an air strike or fire into buildings.
His successor, Gen Petraeus, has vowed to carry on with the policy.
In July, the whistle-blowing website Wikileaks leaked a swathe of documents relating to the Afghan war, which suggested that many civilian casualties were going unreported.
A UN report in January showed that civilian casualties in the Afghan conflict had risen by 14% in 2009 compared with 2008.
It said the "vast majority" of the more than 2,400 deaths had been caused by Taliban attacks.
Below is a selection of comments sent to the BBC from people in Afghanistan
We civilians never feel safe, especially in the provinces of Afghanistan, and all the people can see from this report the number of dead and injured people. We don't feel safe and neither the government nor any other organisations have made any plans to protect civilians. Qais, Kabul
As I see it, the death toll rises year by year. No Afghan civilian will have hope for the future and they will obviously blame foreign forces for this. I just feel safe in Kabul but I can't really travel to other provinces because it isn't totally safe. Nothing is being done to protect civilians. Mukhtar, Kabul
It is ridiculous for Afghans to see that the world's most powerful forces failed to bring security to the country in the past nine years. The so-called insurgents can attack the presidential palace anytime. The international community is simply not honest; it failed to bring security, tackle corruption, poverty and it failed to provide education and employment opportunities. 'Sad Afghan', Kabul
I think it isn't enough that the International Security Assistance Force limit air strikes in a bid to minimise civilian casualties. Instead, focus has to be put on the Taliban by undermining their credibility. In addition, Pakistan has to be pushed. Abasin, Kabul
I don't feel secure, not even at the presence of International Security forces. I don't know what will make them suspicious and when will they open fire. We the civilians can be only protected if the main sources of Taliban are destroyed. Zaman, Kabul