The Islamic State suicide bomber who carried out an attack on a Shi'ite mosque in the Saudi city of Najran on Monday threatened Shi'ites and Saudi soldiers, according to a posthumous audio message purportedly by the attacker.
Najran, close to the Yemeni border, is the historic center of the Ismailis, a Shi'ite sect which has long complained of victimization by Wahhabis, who follow the Saudi state's prevailing school of Sunni Islam.
The 3-minute message, which showed a picture of a man with his face covered, circulated on Islamic State-affiliated Twitter accounts on Tuesday. Reuters could not verify its authenticity.
"My first message is a threat to the rejectionist Ismailis ... you will not enjoy life in the Peninsula," the man, identified as Abu Ishaq al-Hijazi, said, referring to the Arabian Peninsula.
"My second message, to the soldiers of the tyrant who protect the polytheists and their temples in (Saudi Arabia) ... you will not be safe in your homes or your offices and we'll target you as long as the planes of your guardian hit Muslims with Crusader planes in Iraq and Syria."
Saudi Arabia is part of a U.S.-led coalition against Islamic State militants that has carried out a campaign of air strikes against the militants, who have seized parts of Syria and Iraq.
The group is bitterly opposed to Gulf Arab rulers and is seen as trying to stir up sectarian confrontation on the Arabian Peninsula to bring about the overthrow of ruling dynasties.
Monday's suicide bombing, which Islamic State said had targeted the "rejectionist Ismailis", killed one man and wounded several others.
Saudi Arabia has been hit by a spate of deadly shooting and bomb attacks in the last few months, many of them laid at the door of Islamic State, which has urged young Saudi Sunnis to attack targets including Shi'ites.