Saudi Arabia's Islamic Affairs Ministry is investigating 17 mosque imams in the capital Riyadh for not using their Friday sermons to denounce an al-Qaeda attack earlier this month, the English daily Arab News reported yesterday.

The conservative Islamic kingdom is worried that anger at the violence in Syria and Iraq, coupled with hardline teachings by some local religious leaders, could inspire a new generation of militants to again attack domestic targets.

Al-Qaeda in the Arabian Peninsula (AQAP) raided Sharurah, a small Saudi frontier town, from its base in Yemen early this month, killing four border guards and another Saudi citizen before all the attackers were killed or injured.