In a protest apparently assembled largely through a network of banned cellphones, inmates across at least six prisons in Georgia have been on strike since Thursday, calling for better conditions and compensation, several inmates and an outside advocate said.

Inmates have refused to leave their cells or perform their jobs, in a demonstration that seems to transcend racial and gang factions that do not often cooperate.

“Their general rage found a home among them  common ground  and they set aside their differences to make an incredible statement,” said Elaine Brown, a former Black Panther leader who has taken up the inmates’ cause. She said that different factions’ leaders recruited members to participate, but the movement lacks a definitive torchbearer.

Ms. Brown said thousands of inmates were participating in the strike.

The Georgia Department of Corrections could not be reached for comment Saturday night.