(VOVworld) - A suicide bomber attacked a mosque in Shiite-populated eastern Saudi Arabia during Friday prayers, killing four people. The interior ministry said two suicide bombers were prevented from entering the Al-Rida mosque in Mahasen, a neighbourhood in the eastern Al-Ahsa region, by security personnel. It said when security approached to intercept them, one of them responded by blowing himself up at the mosque entrance while an exchange of fire took place with another. The ministry said the second suspect was injured, and arrested with help from citizens. A suicide belt was found in his possession, said the ministry, adding that automatic weapons were also recovered. Since deadly attacks claimed by IS last year against Shiite mosques in the kingdom's east, security has been increased and community guards now inspect visitors to houses of worship. Most of Saudi Arabia's Shiites live in the kingdom's Eastern Province which includes Al-Ahsa, an oasis region where much of the kingdom's oil reserves are located.