CAIRO: Further protests were set to rock Cairo on Friday after President Mohamed Morsi vowed to forge on with a controversial constitutional referendum and condemned street violence that has gripped the capital.

Morsi’s offer in an overnight address for dialogue to resolve the crisis, sparked by his November 22 decree giving himself supreme powers, was rejected by opposition groups.

They said they would step up their campaign against the decree and the referendum set for December 15. Protests were expected to swell after traditional Muslim prayers on Friday.

The opposition coalition, the National Rescue Front, issued a statement saying “the fact that the presidency... persists in ignoring the demands and protests of the people has closed the door on any attempt for dialogue”.

There were fears of more violence after clashes in Egypt on Wednesday between pro- and anti-Morsi protesters that left seven people dead and more than 600 injured.

The army on Thursday cleared the area in front of the presidential palace in the capital of protesters from both sides, and deployed tanks and barbed wire to keep crowds away.

The demonstrations were the biggest since Morsi’s election in June. The street clashes were also reminiscent of the upheaval in February 2011 that toppled former president Hosni Mubarak.

In a broadcast speech late Thursday, Morsi said the referendum on the constitution would go ahead as planned, adding that “afterwards... everyone must follow its will”.

“We respect peaceful freedom of speech but I will never allow anyone to resort to killing and sabotage,” Morsi said.

Morsi offered to host talks with the opposition on Saturday in his offices, but gave no sign that he was willing to make any concessions in the talks.

At least four of Morsi’s advisers have quit over the crisis, and the Cairo stock market has taken a heavy hit from the latest violence.