Jeddah Saudi security forces detained dozens of men, women and children on Tuesday after they staged a rare protest outside a human rights group’s office in Riyadh to demand the release of jailed relatives, activists said.

Protests are banned in the conservative kingdom, a US ally that shows little tolerance towards dissent. But relatives have occasionally gathered outside government offices in the world’s largest oil exporter to demand the release of prisoners they say have been held for long periods without trial.

“They detained six children, 23 women and around 30 men,” Ali Al Hattab, an activist told Reuters from the Saudi capital.

Activists posted pictures on social media showing a crowd surrounded by security forces. Reuters could not verify the images.

Saudi Arabia, which has been a target for Al Qaida attacks, says the prisoners are all held on security grounds. Activists say some are also detained for purely political activity and have never been charged.

An Interior Ministry spokesman did not immediately comment on Tuesday’s incident.

The government has said in the past that prisoners accused of “terrorism-related” charges were undergoing a fair judicial process any relatives who protest are stopped and dealt with according to legal procedures.

Last month the kingdom convicted and sentenced 15 men to between three and 15 days in jail on charges of staging a sit-down demonstration outside a prison in September. The court also handed the men suspended sentences of between 50 and 90 lashes and suspended jail terms of between two and five months.

The incident was condemned by Human Rights Watch which said the Saudi Bureau of Investigation and Prosecution had charged a total of 19 men with ‘instigating chaos and sedition’ and ‘gathering illegally’.

“I believe that such actions worsen the situation. Intimidating and confronting the families will not make them back down on their requests for fair trials,” Al Hattab said.