The US and Afghan military officials say the remote-controlled bombs are hampering progress of the assault on the Taliban bastion of Marjah in Helmand province. <br/><br/>Chief of Afghan Army Staff, Besmillah Khan told newsmen in Nad Ali that hundreds of mines and bombs have been discovered in different areas of Marjah. <br/><br/>A spokesman of the US Marines, Lieutenant Josh Diddams said there has been slow progress in assault because of stiff resistance by Taliban. <br/><br/>Meanwhile, six Taliban including Commander Sirajuddin alias Hikmat Minhas were killed in a NATO air strike in Washer district of Helmand province. <br/><br/>Earlier, another Taliban commander was killed and three others arrested in an overnight raid by the US forces in Chahar Dara district of Kunduz province.