Three brothers have been arrested by Saudi and Kuwaiti authorities for alleged involvement in a suicide bombing by a Saudi man on a Shia Muslim mosque in neighboring Kuwait last month, Saudi state news agency SPA reported on Tuesday.
Islamic State in Iraq and the Levant (ISIL) said it carried out the attack, which killed 27 people and appeared aimed at stoking sectarian hatred in the energy-rich Gulf.
The three Saudi brothers, who were not identified, were "parties to the crime of the sinful terrorist bombing that targeted the Imam al-Sadeq mosque in Kuwait," SPA quoted a security spokesman for the interior ministry as saying.
One was arrested in Kuwait and will be extradited to the kingdom, another was arrested in the western Saudi city of Taif and a third was taken into custody after a shootout at a house near the Kuwaiti border that left two police officers wounded.
A fourth brother lives in Syria and is a member of
ISIL group, the security spokesman added.
The June bombing was Kuwait's deadliest militant attack, and the most lethal in any of the Gulf Arab states since a campaign of Al Qaeda bombings was stamped out in Saudi Arabia a decade ago.
The attack raised concerns about the number of young Saudi men willing to travel to attack Shiites in smaller Gulf Arab states and to make good on a threat by ISIL to step up violence in the holy fasting month of Ramadan.
A Kuwaiti newspaper reported on Monday that 26 people had been arrested in relation to the attack in the country, according to Reuters.
The suspects included four women, and some had relatives who are members of ISIL living in the territory it holds across Syria and Iraq.
Al Jazeera with Reuters