WASHINGTON -- Afghan President Hamid Karzai says he's at "the end of the rope," and a majority of Americans feel the same way.

Of all the past decade's setbacks in the endeavor to form a solid alliance with Afghanistan and defeat the Taliban, the war effort has been driven to a new low by the slaughter of nine Afghan children and seven adults allegedly by a U.S. soldier whose identity had been kept secret until late Friday.

A senior U.S. official said the suspect is Army Staff Sgt. Robert Bales, 38. The official spoke on condition of anonymity because of the sensitivity of the legal case that is in its early stages.

The soldier has arrived at a U.S. military prison at Fort Leavenworth, Kan. Army officials said in a statement that Staff Sgt. Robert Bales arrived Friday night at the prison in northeast Kansas. He was placed in his own cell at the prison adjacent to the U.S. Disciplinary Barracks.

Karzai, who has demanded that Bales be tried under the Afghan justice system, is now insisting that U.S. forces retreat from rural areas immediately and let Afghans take the lead in security next year. But the White House and the Pentagon said Friday that nothing would collapse the war plan, even after the massacre, the inadvertent Quran burnings by U.S. soldiers and the deaths of seven American servicemen at the hands of their allies.

Polls have shown that up to 60 percent of Americans say it's time to end the war in Afghanistan. And that's not lost on the administration.

"The Afghan people are tired of war," Defense Secretary Leon Panetta, just back from Afghanistan, acknowledged on Friday. "The American people share some of that tiredness after 10 years of war as well. All of that's understandable."

But he also said he is confident that Americans realize the U.S. needs to finish its work of stabilizing Afghanistan to ensure that al-Qaida cannot against use that country as a launchpad to attack the United States. His theme -- patience -- is likely to dominate the discourse in Washington and in allied capitals in the lead-up to a NATO summit meeting in Chicago in May.

President Barack Obama called Karzai on Friday seeking clarification on the demand concerning U.S. troops in rural areas. White House press secretary Jay Carney said the leaders agreed to keep discussing the matter, which is at the heart of the military strategy.

"I think that the two men were very much on the same page" about gradually handing over security responsibility to Afghan forces, with U.S. and other international troops switching to a support role throughout Afghanistan sometime in 2013, Carney said.

Another pillar of the war strategy is creating peace talks with the Taliban insurgents. That too suffered cracks in the aftermath of the village massacre. The Taliban said it was no longer talking on terms set by the Americans.

Despite calls for the Army suspect to be tried in Afghanistan, Bales was flown Wednesday to a military detention facility in Kuwait, where that country's officials expressed unhappiness that they were not first consulted.

It remained unclear when the Army would formally charge the soldier, who was said by his lawyer to be reluctantly serving his fourth tour of duty, his first in Afghanistan after three tours in Iraq in his 11-year military career. Much of what is publicly known about the staff sergeant has been disclosed by the lawyer, John Henry Browne, a veteran defense attorney from Seattle who came forward Thursday.

According to statistics provided by the Army on Friday, 107,075 soldiers, or about 20 percent of all active-duty Army members, have had three or more deployments to Iraq or Afghanistan over the past decade.

Browne said that one day before the rampage, the soldier saw a comrade's leg blown off. A senior defense official, speaking on condition of anonymity to discuss possible evidence, said investigators have determined that the suspect had been drinking alcohol before the killings. The official said the role of alcohol in the case is still being studied. Browne has said the suspect's wife reported her husband did not have a drinking problem.

Karzai has been critical of the American effort and on Friday he toughened his talk even more in addressing villagers visiting Kabul from the Panjwai district in Kandahar province, where the slaughter of the 16 civilians took place.

"The fight is not in the villages, not in the houses of Afghanistan," he said, repeating a familiar theme. "It is not safe for you (U.S. troops) in the villages and it is creating a bad name for you."

Karzai has often said the insurgent problem in his country springs from support across the border in Pakistan, not from unrest in villages. Critics of the U.S. and NATO military plan also have said that a large military presence, especially in conservative rural districts, encourages violence and bolsters the Taliban argument that it is fighting a foreign occupier.

But a central tenet of the war strategy is that the presence of U.S. and international troops in certain towns and villages is necessary to separate the population from the insurgents, creating space for local, provincial and national government to take firmer root.

The apparently unprovoked killing spree Sunday in two villages in southern Afghanistan, allegedly by a 38-year-old Army staff sergeant trained as a sniper, is only the latest in a string of missteps by American forces. Their mistaken burning of Muslim holy books at an air base in Bagram last month triggered a wave of violent protests across the country and an apology by Obama.

"As tragic as incidents like these are -- and there have been a string of tragic incidents in recent weeks -- it would be just as tragic, if not more, if we let it affect the overall mission, which is having success," said a Pentagon spokesman, Navy Capt. John Kirby.