The Saudi authorities have arrested 18 suspected spies, including an Iranian and a Lebanese, on charges of espionage for a foreign country, the interior ministry said on Tuesday.
"Sixteen Saudis, an Iranian and a Lebanese were arrested in coordinated and simultaneous operations in four regions of the kingdom," including the capital Riyadh and the holy city of Mecca, the ministry said in a statement.
The suspects, some of whom were arrested in Eastern Province where the kingdom's Shiite minority is concentrated, were working for a foreign country which it did not name, the statement added.
Their arrest was made after the ministry had "received information concerning the involvement of Saudis and expats in espionage on behalf of a another country," said the statement carried by the official SPA news agency.
The suspects "gathered information on vital installations which they provided to the country" they had been working for, it added.
Although the ministry did not reveal the name of the country for which the suspects were allegedly working, the announcement that an Iranian is implicated could point to Iran.
Saudi Arabia and its partners in the six-nation Gulf Cooperation Council have strained ties with Iran which they suspect of supporting Shiite opposition protests in GCC member Bahrain, which like its partners is Sunni-ruled.
News of the arrests came as rights activists on Tuesday reported that Saudi security forces had arrested several Shiites across the kingdom, including two clerics, over the past days for unspecified reasons.
Since early 2011, mainly Shiite towns in Eastern Province have seen sporadic protests and confrontations between police and Shiite residents who complain of marginalisation.
There are an estimated two million Shiites in the Sunni-dominated kingdom of about 27.5 million people.