Saudi police made several arrests as anti-monarchy protesters attempted to stage demonstrations in the kingdom's main cities.
Some arrests were made in the centre of Riyadh
Witnesses reported gunshots, at least six arrests and dozens of people being chased in the streets by security forces in Jeddah on Thursday.
There were reports of minor protests outside government offices in Tabur and Hail but the capital Riyadh was calm.
Exiled dissident Saad al-Faqih had called for protests against the regime.
Mr Faqih's call for peaceful protests came on the anniversary of demonstrations which saw up to 100 people take part.
Interior ministry spokesman Mansur al-Turki said two people were arrested in Jeddah after they fired in the air from a car.
In Riyadh, checkpoints were set up on the main roads and armed police were deployed in force to deter any protests.
Eight people were reportedly detained and questioned in the capital by police in relation to the planned demonstrations.
Armed police were deployed to deter protesters in Riyadh
Mr Faqih had said he was expecting "tens of thousands" of people to turn out, even though political demonstrations are outlawed.
London-based Mr Faqih, who heads the Movement for Islamic Reform in Arabia (MIRA), accuses the Saudi regime of corruption and deviating from the precepts of Islam.
MIRA wants to replace the monarchy with a liberal democratic government.
The government claims Mr Faqih is involved in extremism and says he has strong ties with terrorists. Mr Faqih denies the charges.
In a statement released in the local media, Saudi religious leaders and intellectuals said the protest call was "damaging to the interests of society and the unity of the country".
The Saudi regime has given signs of a willingness to reform.
It has planned municipal elections next year, the first of any kind in years, and has launched a public debate on democratisation.