Security arrested 18 protesters during clashes in Simon Bolivar Square Wednesday near the US Embassy in Cairo, state-run news agency MENA reported.
The day after tens of thousands filled the square in protest against the president's constitutional declaration, protesters once again blocked off traffic in Tahrir Square after partially reopening it earlier in the day.
Demonstrators placed metal barriers in front of square entrances and diverted traffic from near the Egyptian Museum to Bustan Street, closing off the square for the sixth day in a row.
A number of ambulances were stationed in Tahrir due to the ongoing standoff between protesters and security forces in the vicinity of the square. Field hospitals set up at the entrance to Talaat Harb Street received several with bruises and suffering asphyxia from teargas inhalation.
Clashes nearby the square are still ongoing, with protesters pelting security forces with stones and security forces answering them with teargas canisters.
Many of the Mugamma's employees have also left work due to the teargas.
Prime Minister Hesham Qandil met with his Cabinet Wednesday to discuss solutions to the ongoing unrest as well as security and economic issues.
Edited translation from MENA