Saudi Arabia's security services have detained a Saudi Arabian man on suspicion of shooting dead two policemen and wounding two others in separate attacks in Riyadh on Wednesday and in March, state media reported yesterday.

Police found the weapon and car used for the shootings at the home of Rami Abdullah Thulab al-Shammari. Last year militant group Islamic State called on sympathisers in the kingdom to assassinate members of the security services or governnment, non-Muslim residents and members of the Shi'ite Muslim minority. Al- Qaeda has also vowed to bring down Saudi Arabia's ruling family.