Last year was the most lethal for Afghan civilians since the American-led war began here in late 2001, with the Taliban and other insurgent groups causing the vast majority of noncombatant deaths, according to a U.N. survey released Wednesday. The report said 2,412 civilians were killed in 2009, a jump of 14 percent over the previous year. Another 3,566 Afghan civilians were wounded, the report found. The growing number of civilian deaths reflects the intensification of the Afghan war over the same period: American and NATO combat deaths jumped to 520 over the past year, from 295, and the Taliban are more active than at any point in the past eight years. But the most striking aspect of the report was the shift in responsibility for the deaths of Afghan civilians. The survey found that the Taliban and other insurgents killed more than twice the number of civilians as the American-led coalition and Afghan government forces did last year, mostly by suicide bombings, homemade bombs and executions. The 1,630 civilians killed by insurgents -- two-thirds of the total -- represented a 40 percent increase over the previous year. By contrast, the number of civilians killed by the NATO- and American-led coalition and Afghan government forces in 2009 fell 28 percent, to 596, about a quarter of the total number. The report attributed the drop to measures taken by the U.S.-led coalition to reduce the danger to civilians. Since taking over in June, Gen. Stanley A. McChrystal has issued several directives aimed at winning over the Afghan population, sometimes at the expense of making attacks on Taliban fighters. Principal among them was tightening the rules for airstrikes, which have been the main cause of civilian fatalities caused by the NATO forces. Under the new rules, coalition forces caught in a firefight with insurgents may not order an airstrike on a house in a residential area unless they are in danger of being overrun. In the past, airstrikes carried out in the heat of battle in residential areas accounted for several widely publicized episodes of civilian deaths. 