By Mirwais Harooni and Rob Taylor
KABUL (Reuters) - Afghan President Hamid Karzai on Friday lashed out at the United States for failing to fully cooperate with an investigation into the massacre of 16 Afghan villagers by a U.S. staff sergeant and questioned whether only one soldier could have been involved.
A series of blunders by the United States, including the killings in Kandahar province on Sunday and the inadvertent burning of copies of the Koran at a NATO base last month, has further strained already tense relations between the countries.
"This has been going on for too long. You have heard me before. It is by all means the end of the rope here," Karzai told reporters at the heavily fortified presidential palace.
Flanked by senior officials, a tired and sometimes angry Karzai listened to village elders and the families of victims of the massacre, and dressed somberly in black for the start of an expected two days of talks to discuss the killings.
Some at the meeting shouted, some demanded answers, but all said they wanted any soldiers involved punished.
"I don't want any compensation. I don't want money, I don't want a trip to Mecca, I don't want a house. I want nothing. But what I absolutely want is the punishment of the Americans. This is my demand, my demand, my demand and my demand," said one villager, whose brother was killed in the nightime slaughter.
Furious Afghans and lawmakers have demanded that the soldier responsible be tried in Afghanistan, but despite those calls, the U.S. staff sergeant was flown out on Wednesday.
"The army chief has just reported that the Afghan investigation team did not receive the cooperation that they expected from the United States. Therefore these are all questions that we'll be raising, and raising very loudly, and raising very clearly," Karzai said.
Karzai appeared to back the belief of the villagers, and many other Afghans including the country's parliament, that one gunman acting alone could not have killed so many people, and in different locations some distance apart.
"They believe it's not possible for one person to do that. In (one) family, in four rooms people were killed, women and children were killed, and they were all brought together in one room and then put on fire. That one man cannot do," Karzai said.
With twin investigations still underway by both U.S. and Afghan officials, any discovery of more than one soldier involved in the massacre would be a disaster for NATO, with Western leaders needing to win over Afghans ahead of a withdrawal by most foreign combat troops in 2014.
Civilian casualties caused by NATO forces hunting insurgents are a major source of friction between the Afghan government and its Western backers, and have damaged efforts to win the "hearts and minds" of locals in the decade-old war.
"Our families are finished and our houses are destroyed," said a furious Hajji Abdul Samad Aka, who lost 11 members of his family in the killings in two villages of Panjwayi district.
An unnamed U.S. official told The New York Times the attack by the accused soldier was a result of "a combination of stress, alcohol and domestic issues - he just snapped."
The lawyer for the soldier said the staff sergeant was upset at having to do a fourth tour of duty in a war zone and was likely suffering from stress after seeing colleagues wounded.
Anger over the massacre spilled into weekly Friday prayers at a major mosques in central Kabul with one cleric calling the shooting "unforgivable" and questioning how a soldier with alleged mental problems could be in the U.S. military.
"Revenge for the blood of these victims will be taken either today, tomorrow, in 10 years or the next 100 years," said Mullah Ayaz Niazi at Wazir Akhbar Khan mosque in Kabul's diplomatic enclave, which is also home to NATO headquarters.
The soldier accused of the shooting was attached to a small special forces compound similar to others around the country which underpin NATO's anti-insurgent strategy.
On Thursday, Karzai called for NATO troops to leave Afghan villages and confine themselves to major bases, underscoring fury over the massacre and clouding U.S. exit plans.
He also demanded the handover of security to Afghan police and soldiers by 2013, a year ahead of schedule.
Such a move could undercut U.S. President Barack Obama's strategy for Afghanistan and hamper efforts to mentor Afghan police and help with local governance.
In a further blow to NATO hopes of a negotiated end to the decade-old war, the Afghan Taliban said they were suspending nascent peace talks with the United States, following the massacre and ahead of the traditional summer fighting months.
The United States said it was committed to political reconciliation involving talks with the Taliban but progress would require agreement between Kabul and the insurgents.
"The Taliban leadership were and may still be serious about talks, but instead of discussing how to end the war, they will now be persuading the rank and file to go out again this year and fight," Kate Clark of the Afghanistan Analysts Network said.
"That another round of fighting and killing is now on the agenda is a difficult prospect to face," she wrote in a blog.
(Writing by Jack Kimball, Editing by Rob Taylor and Sanjeev Miglani)