King Abdullah had offered a $67bn package to stave off unrest sweeping the region [REUTERS]

Several protesters were arrested in Saudi Arabia on Sunday at a demonstration demanding the release of thousands of prisoners, held captive for years without trial.

They were among dozens of men and women who tried to push their way into Riyadh's interior ministry building, which was fortified with up to 2,000 special forces and 200 police vehicles, according to the Associated Press news agency.

"We have seen at least three or four police vehicles taking people away," said an activist there who declined to be named.

"Security forces have arrested around 15 people. They tried to go into the ministry to go and ask for the freedom of their loved ones."

Some people were seen arguing with police but were not shouting chants or bearing protest placards, at the third such demonstration this month by families demanding information on the fate of relatives, held secretly on security or terrorism charges.

Protests are banned in the kingdom, the world's top oil exporter.

Saudi interior ministry spokesman Mansour al-Turki did not confirm the arrests, saying: "There are many people who come to the ministry to see different officials for different reasons."

King Abdullah, the ruler of Saudi Arabia - a country with some two-thirds of its 25 million population under 30 - on Friday offered a $67bn worth of wage increases, jobs and construction projects, but gave no political concessions.

The move was seen as an attempt to stave off the unrest that has swept the region.