Twenty-seven percent of Afghans polled said the attacks can be justified. Last year, the number was just 8 percent as former NATO commander Gen. Stanley McChrystal issued strict guidelines limiting the use of force in an effort to reduce civilian casualties.
This year's sharp increase brings the number back to levels seen earlier in the nine-year war.
The poll, which has a margin of error of 3.5 percentage points, was based on face-to-face interviews with a random sample of nearly 1,700 Afghan adults in all 34 of the country's provinces. It was conducted from Oct. 29-Nov. 13 by ABC News, the BBC, ARD German TV and The Washington Post.
The number of Afghan civilians killed or injured soared 31 percent in the first six months of the year, but they were largely caused by Taliban attacks, according to the United Nations.
Casualties from NATO and Afghan government forces dropped 30 percent, compared with the first half of 2009, mainly because of curbs on the use of airpower and heavy weapons, the U.N. said.
Monday's survey also showed Afghans are losing confidence in the United States and NATO to provide security in their country, and they are more willing to see a negotiated settlement with the Taliban than they were last year.
Just 36 percent of those polled expressed confidence in the U.S. and NATO to bring stability, down by 12 percentage points from last year and down by 31 percentage points since 2006. The survey also said 73 percent favor a negotiated settlement with the Taliban, up by 13 percentage points since 2007.
Also Monday, two NATO service members was killed in insurgent attacks in southern Afghanistan where Afghan and international troops are penetrating Taliban strongholds, the military coalition said.
NATO did not disclose the nationalities or any details on how the service members died.
The British Defense Ministry said a British soldier who died in southern Afghanistan on Sunday might have been killed by friendly fire. He was shot while on patrol in Nad Ali district of Helmand province.
So far this month, nine NATO troops have been killed in Afghanistan, including at least three Americans. Since the beginning of the year, 669 coalition service members, including at least 460 Americans, have died.
In the main southern city of Kandahar, meanwhile, a policeman was killed in a roadside bomb explosion, said Asadullah Khan, a doctor who saw the body of the deceased in Kandahar hospital.
The Afghan intelligence service, meanwhile, said it had arrested a number of militants in different parts of the country in the past 10 days, including a group of four would-be suicide bombers in Kabul who were planning a suicide attack in Baghlan province.
As violence continues, President Hamid Karzai is trying to get traction on a new peace and reconciliation program, which has two objectives: Reconcile with top Taliban leaders who agree to renounce violence, embrace the constitution and sever ties with terrorists, and lure foot soldiers off the battlefield to reintegrate into Afghan society. The plan, which is just starting to be developed across the nation, seeks to attract 25,000 to 35,000 fighters with promises of jobs, literacy and vocational training, and development aid for their villages.
On Monday, Former Afghan President Burhanuddin Rabbani, leader of the country's newly formed peace council, and Mohammad Masoom Stanekzai, a top adviser to Afghan President Hamid Karzai, traveled to Kandahar to discuss Afghanistan's peace and reintegration program with provincial governors in the south.
NATO spokesman Brig. Gen. Josef Blotz said Monday that more than 600 insurgents have laid down their weapons in recent months and joined the peace process with the Afghan government. The coalition is highlighting the program to demonstrate progress in the war, which will be the focus of President Barack Obama's review of the war strategy to be released within days.
Blotz said there have been 25 cases of fighters wanting to switch sides, including about 150 insurgents in Baghlan province in the north. Local Afghan officials have also reported reintegration activity in Herat, Badghis and Nangarhar provinces.
"We are putting a lot of pressure on the insurgency - using military and nonmilitary means of all sorts," he said at a news conference Monday. "Hundreds of insurgents are simply frustrated because they are sent into battle by people - senior Taliban leadership hiding away in Pakistan ... so they are simply fed up."
Associated Press writers Rahim Faiez and Deb Riechmann