Saudi Arabia says the suicide bomber behind Friday's attack on a Shiite mosque in the port city of Dammam that killed four people was a Saudi national.

The Interior Ministry on Wednesday identified the bomber as 19-year-old Khalid Ayed Mohammed Wahabi Shammari. He disguised himself as a woman and blew himself up in the mosque parking lot after being prevented from getting inside.

The ministry says the explosive used was RDX, a military-grade compound that was also deployed in a suicide bombing at another Shiite mosque a week earlier that left 22 people dead.

The Islamic State group has claimed responsibility for both attacks. It sees Shiites as heretics and seeks the overthrow of the Saudi monarchy.