The rights group has called for a full investigation into the physical and psychological torture of the detainees

The Saudi-based Human Rights First Society has called for the release of 100 protesters amid reports that some of those arrested have been tortured.

The rights group has called for a full investigation into the physical and psychological torture of the detainees, AFP reported. It says the protesters were mainly arrested in the cities of Safwa, Qatif, and Hassa in the east of the country during peaceful rallies last week.

Saudi Arabia's Interior Ministry has declined to comment on the report. Riyadh has recently stepped up its clampdown on anti-government protesters in response to protests in the kingdom.