WASHINGTON (Reuters) - The United States repeatedly told Pakistan that Washington would send American forces into that country if it had evidence that Osama bin Laden was hiding there, according to current and former US officials. The message that the United States would not hesitate to send American operatives into Pakistan to get bin Laden was transmitted to top Pakistani officials on multiple occasions by the administrations of presidents Barack Obama and George W Bush, said a US national security official who asked for anonymity when discussing sensitive information. A former senior US counter-terrorism official, also speaking on condition of anonymity, said there was an understanding between Washington and Islamabad that amounted to an acknowledgment by Pakistani authorities that the United States would take unilateral action on Pakistani soil if it had intelligence on the al-Qaeda leaders whereabouts. The current US official said the message that the United States would dispatch forces to go after bin Laden if it found him in Pakistan was repeatedly passed on to Pakistani authorities so that, at a minimum, Islamabad should have had no illusions about the US position.