A number of Shia community leaders in Saudi Arabia have signed a statement condemning the recent arrest of 16 Shia citizens on allegations of spying.
The statement called for political reform and an end to what it called a policy of playing the sectarian card.
The Saudi interior ministry said those arrested were gathering information about installations and vital areas for another country.
The country said to be running the spy network was not named.
However, it is widely assumed to be Iran.
Saudi Arabia, which is predominantly Sunni Muslim, has recently repeatedly found itself at odds with Iran, an overwhelmingly Shia Muslim nation.
Tensions deepened last year when Saudi Arabia deployed troops to the Gulf island kingdom of Bahrain to help crush a Shia-led uprising there.
There have been low-level protests for more than a year in the Qatif region of the oil-rich Eastern Province where most of Saudi Arabia's Shia minority live. Approximately 15% of Saudis are Shia.
Human rights groups say there is systematic discrimination in Saudi Arabia against Shia Muslims in education, employment and justice.
Saudi Arabia follows the puritanical form of Sunni Islam known as Wahhabism, and many Wahhabi clerics regard Shia Muslims as unbelievers.