The inquiry has been ordered by the head of U.S. Central Command, and was meant to examine how exactly U.S. Forces have been operating in Afghanistan and will operate in future.

The report suggests the U.S. Army faced difficulties while carrying out the operation in the western province of Afghanistan on May, 4, which led to some technical mistakes occurring.

The U.S. Military has reportedly acknowledged some responsibility for civilian deaths, but has said that the mistakes are not so serious to consider punishment for them.

Defense Secretary Robert Gates expressed his support for the probe to be released, while at a news conference on Thursday. He also stressed that reducing civilian casualties is a common challenge for the entire international force in Afghanistan, and is a top priority for the new U.S. Commander in the region.

“It is clear that we need to do much more to overcome what I believe is one of our greatest strategic vulnerabilities,” Gates said.

The chairman of the U.S. Joint Chiefs of Staff, Admiral Mike Mullen, also backed the report and pointed that the document suggested shortcomings in training and how orders are transferred through the chain of command, AFP news agency reported.

"There were command-and-control challenges, chain-of-command challenges, some training issues that we've got to address," said Mullen, appearing with Gates at the news conference,” Mullen said.

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