The phone number to report Iowa caucus results was posted on a fringe internet message board on Monday night along with encouragement to “clog the lines,” an indication that jammed phone lines that left some caucus managers on hold for hours may have in part been due to prank calls.

Several officials at caucuses attended by NBC News reporters on the Vote Watch team struggled with lengthy hold times that made it impossible for them to report results.

An Iowa Democratic Party official said the influx of calls to the reporting hotline included “supporters of President Trump who called to express their displeasure with the Democratic Party.”