Afghan soldiers' incompetence raises concerns about U.S. withdrawal plans (CBS News) MANSURABAD, Afghanistan - A suicide bomber drove his car into a U.S. convoy in Afghanistan's capital Thursday, causing a massive explosion. Six Americans died: Two soldiers and four civilian contractors. Nine Afghans were also killed. Islamic militants claimed responsibility. American combat troops are due to leave Afghanistan after next year and are training Afghans to take over security. But are they ready? Afghanistan suicide blast targeting NATO convoy kills 2 U.S. troops, 4 American contractors Deadly day for U.S. troops in Afghanistan Panetta arrives in Afghanistan as 2014 troop withdrawal looms U.S. troops may be pulling back from other parts of Afghanistan, but not in Mansurabad. Will Neves from Spanish Fork, Utah, and his men were going to search for roadside bombs, but first he needed to round up his Afghan partners. With U.S. helicopters providing cover, Neves' platoon followed the Afghan soldiers. U.S. soldiers in Afghanistan discuss a plan to bring Afghan soldiers with them on a search for roadside bombs. Putting Afghans in the lead isn't just a military doctrine. On foot patrols like this, it is a daily reality: Afghans out in front backed up by American soldiers. About two miles into the patrol, there was a problem. The Afghan soldiers had forgotten batteries for their mine detector, and needed the U.S. soldiers to help. The American soldiers didn't say a word, but their frustration was obvious. While the handful of Afghan soldiers spread out ahead, U.S. soldiers were more cautious. Step by step, they carefully followed a path marked by powder. When the minesweeper detected a possible threat, it was marked with a warning to steer clear. "The main thing is just stay in a file," Neves said. Stay right behind one another. It's the same when the soldiers are taking fire. Yeah, we've been here a long time, they know our tactics. If they shoot at us, we're going to go seek cover. And a lot of times that's where they've placed IEDs. So right now we're just trying not to get blown up, basically. The strategy of putting Afghan forces in the lead is supposed to mean that U.S. troops stay out of local villages. But that's not what CBS News saw. U.S. troops visited at least once a day to back up their Afghan partners. The Taliban is still a threat. A U.S. troops gear up for another fighting season with their Afghan partners, the idea of an American withdrawal seems a distant idea.