Police trucks and armored vehicles deployed outside the parliament in a usually busy boulevard in central Cairo.
Again, police gave a warning before firing water cannons, participants in the rally said.
The melee outside forced the suspension of a session of the constitutional panel, held in the parliament building.
At least 35 prominent activists were detained by police and held in the parliament grounds, said Mohammed Abdel-Aziz, a lawyer who was among those detained.
Azab was also among those held in parliament.
Earlier, she said she was briefly held by police in the first protest, but an officer let her go to tell her colleagues that no protests will be allowed without permits.
“I told him: You want me to take a permit after January 2011?” she said, referring to the start of the anti-Mubarak uprising.
“He said: This is what the moment calls for,” she said, adding, “They want to bring us back” to before 2011.
She said for the authorities, the secular activists—though smaller in numbers—“are more of a nuisance than the Brotherhood because we don't have a central leader like the Islamists' guide to tell us what to do.”
Security forces had heavily deployed across town where Morsi supporters had planned to hold a rally later Tuesday. Few pro-Morsi protests materialized in the capital.
Skeptical of both Morsi's Muslim Brotherhood group and the military, activists who spearheaded the 2011 uprising against Mubarak have been organizing limited but rare non-Islamist protests in recent weeks demanding justice against police officials who killed hundreds of protesters during the tumultuous past three years.
The activists have openly clashed with the military before—when generals directly ruled Egypt following Mubarak's fall—and then with the Brotherhood during Morsi's one year in office.
International criticism of the protest law has also grown.
