US officials were watching with growing concern Friday as reports suggested Pakistan was massing troops on the India border. Such a move raises double-barreled scenarios: A possible confrontation between two nuclear powers and a shift by Pakistani military away from battling the Taliban along its western Afghan edge. White House spokesman Gordon Johndroe said the US hopes that both sides will avoid unnecessarily raising tension. US military leaders have been urging both India and Pakistan to exercise restraint in the wake of the deadly Mumbai attacks that many believe originated with Pakistan-based militants. Early Friday, US intelligence and military officials were still trying to determine if the reported troop movements were true, and, if so, what Pakistan's intent may be. And they cautioned that the reports may be exaggerated, aimed more at delivering a message than dispatching forces.