Syrian forces fired nail bombs to disperse tens of thousands of protesters Friday in the Damascus suburb of Douma and the demonstrators retaliated with stones, activists said.

The Britain-based Syrian Observatory for Human Rights said at least 24 protesters were hurt when the security forces fired the "nail bombs to disperse tens of thousands of demonstrators in Douma."

"An activist in the city told the Observatory that he was hurt by shrapnel from those bombs," the watchdog added in a statement received by AFP in Nicosia.

The reported use of nail bombs could not be independently verified.

The Observatory said that demonstrators "hurled stones" at the security forces in the vicinity of city hall when they fired stun grenades and tear gas at them.

According to the Observatory, more than 60,000 Syrians flooded the streets of Douma and were heading to the city hall building when the confrontations broke out.

"Between 60,000 and 70,000 demonstrators are heading to city hall," it said, adding that this was "the biggest ever demonstration" to take place in the restive suburb north of Damascus since March.