Hundreds of troops of Afghanistan's opposition Northern Alliance, backed by tanks, massed at the front line just north of Kabul late Friday and commanders said they expected to advance within hours. A cameraman saw about 800 Northern Alliance fighters march toward the front line along with four tanks and 40 artillery pieces while US jets roared overhead, dropping their bombs on Taliban positions overlooking the opposition-held Bagram airport. Commanders at the front said they expected to launch an offensive at about 2.00 am (0300 IST) to take the Taliban positions that have made the airport unuseable. Bureau Report