Saying that Sunday's murders of 16 civilians has him at "the end of the rope," Afghan President Hamid Karzai "lashed out at the United States" today, The Associated Press reports.

According to the wire service and other news outlets such as the BBC, Karzai also said that family members of the victims tell him that they're convinced there was more than one shooter.

The BBC's Lyse Doucet reports that Karzai referred to the information from American military officials that only one soldier, an unidentified Army staff sergeant, was involved as a "supposed" account of what happened.

The AP adds that "the Afghan leader stressed that he wants a good relationship with the U.S. but that it is becoming increasingly difficult. He insisted that the U.S. needs to respect Afghan culture and laws."

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