JERUSALEM—Several high-profile former U.S. officials, some with close ties to the Obama administration, met with leaders of the Palestinian militant group Hamas in recent months, raising hope inside the group that its views are being heard at the White House. White House officials and participants in the talks emphasize the meetings weren't sanctioned by Washington. U.S. officials say there has been no change to Washington's insistence that Hamas take a number of steps before official dialogue can begin.