The U.S. military is unsure whether it killed a Taliban (search) militant targeted in an airstrike that also killed nine children in Afghanistan, the chairman of the Joint Chiefs of Staff said Tuesday.

Shortly after the Saturday strike, American military officials said they believed the airstrike killed Mullah Wazir, a former Taliban district commander suspected of attacking aid groups and highway construction workers. But local villagers say the man killed was Abdul Hamid, a laborer in his 20s, and that Wazir left the area before the airstrike.

Joint Chiefs of Staff Chairman Gen. Richard Myers (search) told reporters on Tuesday it was unclear who was killed in the raid, but the top U.S. commander in Afghanistan, Brig. Gen. Lloyd J. Austin III, is starting an investigation.

Austin and other U.S. military officials have visited the site of Saturday's airstrike and offered to help the villagers. Defense Secretary Donald H. Rumsfeld (search) offered condolences to the families of the dead children.

Myers said U.S. forces have tried hard to avoid killing civilians. Afghan leaders have said the children's deaths could help turn public opinion against the Americans.

"There are risks any time you go after any target," Myers said. "But I can tell you the kind of vetting that the process goes through, from the beginnings of intelligence to the final operation, is exquisite. We're not going to be perfect, and we found that out in Afghanistan."

Rumsfeld returned Sunday from an overseas trip that included a stop in Afghanistan. He said the issue of Afghanistan's opium poppy crop did not come up in his discussions with Afghan President Hamid Karzai.

"People are projecting and estimating that the [poppy] crop this year will be sizable and that it will represent a rather major chunk of the illegal drugs that end up moving into Europe and Asia," Rumsfeld said. "It's a concern to the Karzai government. It's a concern to the coalition. The Brits have taken a lead on this issue and certainly the United States has tried to be helpful."

The defense secretary said he could not confirm a published report that American representatives were meeting with an Afghan warlord's subordinates to persuade them to disarm and form democratic political parties. The Los Angeles Times' report said U.S. officials had met with four commanders under Gulbuddin Hekmatyar, a warlord who has vowed to wage a holy war on coalition forces in Afghanistan.

Rumsfeld said, however, he hoped the report was true.

"We're constantly trying to get more people to be with us than against us, and goodness knows, Hekmatyar is not with us," Rumsfeld said. "He's a person who's caused a whale of a lot of trouble in that part of the country. And to the extent we can get folks in that general neighborhood moved away from him, it would be a very good thing."