The number of security incidents recorded during the first eight months of the year was nearly 40 percent higher than in the same period of 2010.
While about two-thirds of the violence was concentrated in the south and southeast, suicide attacks became more common outside that area, with the central region accounting for one in five.
The number of complex suicide attacks has jumped by half in the year to date from a year earlier, and made up a greater proportion of all suicide attacks.
Civilian casualties, already at record levels for the first half of the year, rose 5 percent in the June-August period compared with last year, with insurgents linked to three quarters of those deaths and injuries.
The NATO-led International Security Assistance Force (ISAF) said it disputed the report’s findings and would provide its own data on Thursday, but gave no further details.
“Following an initial evaluation, ISAF found it (the report) inconsistent with the data that we have collected,” ISAF spokesman Jimmie Cummings said in a statement.
The report to the UN Security Council by Secretary-General Ban Ki-moon highlights the challenges facing Afghanistan’s troubled government and the NATO-led coalition, which started its gradual handover of security responsibility to Afghan police and the army in July.
It said transition areas, which included Bamiyan and Panjshir provinces and southern Lashkar Gah city “continue to face a resilient insurgency that is attempting to challenge the capacity of the Afghan forces.”
A total of 1,841 civilian deaths and injuries were recorded from June to August, of which 282, or 12 percent, were attributed to Afghan or foreign forces.
Air strikes were the leading cause of deaths by coalition forces, killing 38 civilians in July, the highest number recorded for any month since February 2010, the report said.
The overall rise in civilian casualties was attributed to increased use by insurgents of home-made bombs and suicide attacks, which accounted for 45 percent of deaths and injuries.
The use of such devices in attacks across Afghanistan had nearly doubled compared with the June-August period last year.
Higher levels of insecurity were accompanied by a rise in the number of internal refugees, with around 130,000 people abandoning their homes in the first seven months of the year, up nearly two-thirds from the same period a year earlier.
The U.N. assessment of humanitarian needs suggested as many as 1.3 million Afghans may require food aid in the next 10 months as a result of the conflict and “drought-like conditions” after a year with low rainfall.
It also noted a 65 percent increase in eradication of opium poppy fields in 2011 from a year earlier, though it said the attacks on eradication teams had sharply increased, with 48 such incidents this year compared with 12 in 2012.
UAE leads both the Ladies’ Team and Under-15 Girl’s Team divisions at Riyadh Golf Club tournament