Saudi interior ministry said on Saturday that protests were illegal, amid various calls for demonstrations demanding change in the ultra-conservative kingdom, state television said.

Security forces would use all measures to prevent any attempt to disrupt public order, state news channel al-Ekhbariya said in an alert without giving details.

The ban follows a series of protets by Saudi Shi'ites in the kingdom's east in the past weeks mainly to demand the release of prisoners they say are long held without trial.

Saudi Arabia's Shi'ite minority mostly live in the east, which holds much of the oil wealth of the world's top crude exporter and is near Bahrain, scene of protests by majority Shi'ites against their Sunni rulers.

Saudi Shi'ites they complain they struggle to get senior government jobs and other benefits like other citizens.

The government of Saudi Arabia, an absolute monarchy without an elected parliament that usually does not tolerate public dissent, denies these charges.
Last week, King Abdullah returned to Riyadh after a three-month medical absence and unveiled $37 billion in benefits for citizens in an apparent bid to insulate the kingdom from protests spreading in several Arab countries.