The Saudi interior ministry has said it has dismantled two terror cells planning attacks on Western targets in the country.
Two Saudis and six Yemenis were arrested after the alleged cells were detected in the capital Riyadh and Jeddah.
They were thought to be planning explosive attacks on ex-pat communities within the country and were said to be in an advanced stage.
A spokesman for the Interior Ministry said the authorities had monitored the two cells for several months and that the cells had been in touch with al Qaeda outside Saudi Arabia.
The Riyadh cells had apparently been recruiting members to carry out criminal operations targeting security, citizens, residents and public facilities.
They had reached an advanced stage in planning, including the preparation and testing of explosives which had led to one member of the cell losing his fingers, it was reported.
Security forces arrested the alleged leader of the cell, who then divulged information on its members, plans, equipment and how they were in contact with al Qaeda.
Three sites were also being investigated, including a room attached to a mosque in Riyadh where chemicals used to manufacture explosives were found.
Links between the two cells led to the arrests of two Saudi people in Jeddah. One had also been testing chemical explosives.
In 2003, 35 people were killed in attacks on Riyadh compounds where ex-pats tend to live.
