"So.......this can't be good. Everyone is freaking out in the hotel," Steve Wheatcroft tweeted at 8.14 A.M. local time (1814 GMT).
Another player, J.J. Spaun, took refuge in his hotel basement.
"Barely any service. Can you send confirmed message over radio or tv," he said in a tweet at 8.26 A.M.
Two minutes after that, John Peterson revealed the evasive steps he had taken.
"Under mattresses in the bathtub with my wife, baby and in laws. Please lord let this bomb threat not be real," tweeted Peterson, who was tied for second place halfway through the tournament.
World number four Justin Thomas, the defending champion, however appeared not to be as perturbed as his fellow professionals.
"To all that just received the warning along with me this morning ... apparently it was a 'mistake' - hell of a mistake!! Haha glad to know we'll all be safe," Thomas tweeted at the same time as Spaun.
Speaking after the third round, which started on time at Waialae Country Club, Thomas said he had not got the original warning and was only aware after he received a screen shot from fellow pro Tom Lovelady.
"I was like 'there's nothing I can do,'" Thomas said of his original equanimity.
"I sat on my couch and opened up the sliding door and watched TV and listened to music.
"I was like, if it's my time, it's my time."
(Reporting by Andrew Both in Cary, North Carolina; Editing by Greg Stutchbury)
