More Afghans feel that attacks against foreign forces are justified than at any time since 2005, a survey suggests.
The poll found 27% of people felt attacks against US or Nato troops were justified - though 64% disagreed.
The survey of 1,691 Afghans, for the BBC and other news groups, suggests that security has overtaken the economy as the greatest concern.
The Taliban remain unpopular, but an increasing number of Afghans (73%) said they backed a negotiated settlement.
Some 23% said they supported continuing the fight against the Taliban - a similar level of backing as in previous years.
The Afghan Centre for Socio-Economic and Opinion Research carried out the national survey between 29 October and 13 November this year.
It found that support for President Hamid Karzai remains strong, despite recent corruption allegations and an election last year widely condemned by international observers.
Some 62% of those polled rated his leadership as good or excellent, compared with 72% in 2009 and 52% a year earlier.
The findings from the poll - carried out for the BBC, ABC News, Germany's ARD and the Washington Post - mirror other surveys which have shown strong support for Mr Karzai.
In general, Afghans felt less confident about the future than they did a year ago - 65% saying they felt life would be better in a year's time, compared with 71% who expressed optimism last year.
Fifty-nine percent of those asked said they felt the country was going in the right direction, down from 70% the previous year.
This year has been the bloodiest yet in the US-led coalition's nine-year war against Taliban forces, with civilian casualties at an all-time high.
The number of those surveyed who blamed American forces for the violence rose from 5% last year to 14% this year.
The numbers blaming the Taliban for the killing fell from 42% to 33%.
But support for foreign involvement in Afghanistan is still very strong - with 63% saying they back the presence of US forces and 54% supporting Nato/Isaf.
Just 11% expressed support for Taliban fighters.