Despite the rapid advance of army and Marine forces across Iraq over the past week, some senior US military officers are now convinced that the war is likely to last for months and will require considerably more combat power than is now on hand there and in Kuwait, senior defence officials said on Wednesday.The combination of wretched weather, long and insecure supply lines and an enemy that has refused to be supine in the face of US combat power has led to a broad reassessment by some top generals of US military expectations and timelines, The Washington Post learns. Some of them see even the potential threat of a drawn-out fight that sucks in more US forces. Both on the battlefield in Iraq and in Pentagon conference rooms, military commanders were talking on Wednesday about a longer, harder war than had been expected just a week ago, the officials said. ‘‘Tell me how this ends,’’ one senior officer said.While some top planners favour continuing to press north, most army commanders believe that the pause in army ground operations that began on Wednesday is critical. A relatively small force is stretched thin over 480 km and much of the army’s killing power, in more than 100 AH-64 Apache attack helicopters, has been grounded by persistently foul weather or by battle damage from an unsuccessful pre-dawn raid on Monday.To the east, the Marine Corps advance on the city of Kut was also hampered by skirmishing along its supply line and fuel shortages at the front. More forces are coming, including the army’s 4th Infantry Division, which has begun pushing equipment from 35 ships into Kuwait after Turkey refused to allow a second front into northern Iraq. But it will probably take the better part of a month for that tank-heavy division to get into position and provide combat power.Other forces heading to this region, including the 3rd Armoured Cavalry Regiment, at Fort Carson, Colo., and the 1st Cavalry Division, at Fort Hood, Texas, will require months to move their tanks and other armour from their bases into combat, the defence officials said.Pentagon spokesmen rejected that pessimistic assessment on Wednesday and insisted that the war is still going according to plan. ‘‘The plan has moved almost exactly with expectations,’’ Army Maj. Gen. Stanley McChrystal said at the briefing. But Secretary of State Colin Powell, a former chairman of the Joint Chiefs of Staff who maintains close ties with some senior army generals, seemed to break with part of that assessment, saying in an interview with National Public Radio broadcast on Wednesday that it is becoming evident that the war ‘‘may take a little bit longer, don’t know how long.’’In the short term, the army plans to secure its strained supply lines with a portion of the 82nd Airborne Division, now positioned near Kuwait City, and troops from the 101st Airborne Division, which is gathering at a forward operating base deep inside Iraq, army sources said.Heroic efforts have been made by truck companies and other logisticians, but a certain amount of chaos has developed, exacerbated by sniping and immense traffic backlogs from the Kuwaiti border. That traffic jam also has undermined Bush administration plans to quickly follow the US military advance with tons of food and ‘‘we’re not going to rush headlong into the city, absolutely fruitless to do so and suicidal at best,’’ one Pentagon oficial said. ‘‘The goal is to encircle the city and take it on our terms.’’Retired Army Col Benjamin Covington, an expert in tank warfare, agreed, saying that, ‘‘Everything on the ground depends on the arrival of the Fourth Infantry Division. I expect the final battle for Baghdad will occur when they are in the fray.’’Some Pentagon insiders and defence experts vigorously contested these pessimistic assessments. ‘‘This is not a crisis,’’ said former Speaker of the House Newt Gingrich. He said the key fact to keep in mind was that US forces drove to within 80 km of the capital in just six days without being engaged by regular Iraqi forces. ‘‘If they come out and fight us, they will be annihilated,’’ he said. Retired army Lt Col Andrew Krepinevich agreed with Gingrich’s view. —(LA Times-Washington Post)