DUBAI, May 24 (Reuters) - Saudi Arabia's King Salman said on Sunday he was heartbroken over a suicide bombing that killed 21 people in eastern Saudi Arabia, saying anyone linked to the attack or who sympathises with it will be brought to justice, state news agency reported.

"We were pained by the enormity of the crime of this terrorist aggression which contradicts Islamic and humanitarian values," the king said in a message to Crown Prince Mohammed bin Nayef, who is also the interior minister.

"Any participant, planner, supporter or sympathiser with this heinous crime will be held accountable, tried and will receive the punishment he deserves," he said, adding that Saudi Arabia would never stop fighting militants.

(Reporting by Omar Fahmy; writing by Sami Aboudi; editing by David Clarke) ((Sami.Aboudi@thomsonreuters.com; +97143918301;))

Keywords: SAUDI SECUITY/KING