Clashes around the Interior Ministry in downtown Cairo resumed at around 5 pm after hours of quiet.
State owned Nile TV said that after a truce was made between protestors and security, some protestors hurled stones at police, who responded with tear gas.
Live footage on Al-Jazeera Mubasher Misr shows scores of protestors gathered in Mansour Street, close to the Interior Ministry, with tear gas filling the air.
The footage also shows some protestors carrying stones.
In the early hours of Saturday, some protestors tried to convince others in the vicinity of the Interior Ministry to return to Tahrir Square.
The unrest is part of nationwide protests in the wake of Wednesday's Port Said football disaster, which killed at least 71 people. Protesters blame security forces for the disaster. Twelve protesters have been killed in the past three days.
