Such numbers did not show up, but the threatened show of defiance to the kingdom's ban on protests caused the government to deploy large numbers of security forces, checkpoints, and helicopters.
Several hours after the protests were to begin, the assembly area for the Riyadh protest bustled with police and special forces -- but no demonstrators. Helicopters circled overhead and police stopped motorists at checkpoints.
Police frisked a man who was lying on the ground and placed him in a police car.
Interior Ministry spokesman Brigadier General Mansour al-Turki said two men were arrested in Jiddah after firing a pistol in the air, and a security official speaking on condition of anonymity said they might be connected to Fagih.
During the day, Fagih's group told reporters the assembly point had changed to two other locations. But reporters who went to the locations found normal pedestrian traffic and no police.
In Jidda, at least six people were seen being arrested and dozens in small groups were seen running from police. At one point, a volley of gunshots could be heard in an area where protesters were trying to gather. It was not immediately clear what happened.
Fagih had called the protests via his satellite television and radio stations and website. In the group's boldest challenge to the monarchy, its website spelled out "immediate procedures to be taken after the demise of Al Saud" -- referring to the royal family.
The royal family will leave behind "a massive legacy of poverty, unemployment, crime, ailing infrastructure, and scores of prisoners, tortured ones and a social chaos," the website statement said, calling on security officers to retain their positions to prevent chaos after the monarchy's downfall.
Fagih could not be reached yesterday. His London telephone was continuously engaged.
In the northwestern city of Tabuk, a few people demonstrated outside government buildings, witnesses said, and similar gatherings were reported in Hail. No confrontations with the police occurred, the witnesses said.
Fagih's group says it seeks to replace the monarchy with a liberal, democratic government. In today's Saudi Arabia, the king wields absolute power. There are no legal political parties. Public protests are banned and the press is controlled.