WASHINGTON - The joint Nato-Afghan militarys anti-Taliban offensive in the southern Afghan town of Marjah is progressing but more slowly than expected, top US military officials say. Chairman of the US Joint Chiefs of Staff, Navy Adm Mike Mullen, spoke at a Pentagon joint briefing in Washington about US anti-Taliban offensive launched Feb 13 in Helmand province. Mullen, who was joined by US Defence Secretary Robert Gates, said the Taliban have put up stronger resistance in some cases than had been anticipated. However, he said the Afghan and coalition forces are making gains. As you have all been seeing, we are making steady, if perhaps a bit slower than anticipated, progress, Mullen said. The Admiral said the real challenge is clearing booby traps and crude bombs planted by Taliban fighters, the report said.Mullen expressed regret and condolence over what Nato said were the accidental deaths of civilians last Sunday while a Nato airstrike targeted suspected insurgents. Saying war is messy and ugly, he said, We must steel ourselves, no matter how successful we are on any given day, for harder days yet to come. Gates said Gen Stanley McChrystal, commander of coalition and US forces in Afghanistan, is doing everything humanly possible to avoid civilian casualties. But it is also a fact that the Taliban mingle with civilians, Gates said. He said Gen McChrystal is balancing concerns for Afghan civilians and military forces, adding that he would not try and second-guess Gen McChrystal from 9,000 miles away. He is the commander. I have confidence in his judgment, Gates said. A VOA report said at least 16 civilians, about 120 insurgents and 13 Nato troops have died in the Helmand campaign. Agencies add: US Defence Secretary Robert Gates also praised Pakistan over the recent capture of Afghan Taliban leaders but avoided revealing further details of the operations, reportedly carried out with help from the US Central Intelligence Agency. He said it showed Islamabad had made real progress against Taliban militants and underlined the importance of operations on both sides of the border. So I think that the recent events have been another positive indication of the Pakistanis commitment to stabilising this border area with Afghanistan, he said. Gates spoke in the backdrop of Pakistans capture of Mullah Baradar, a top Afghan Taliban leader, two shadow governors of Afghan provinces and reported arrest of another militant leader. When asked whether the arrests might help turn the tide in the eight-year war, Adm Mullen cautioned against putting too much stock in any single event. He said, Its just too early. The long view here is the best view, Mullen said.