At least one person was killed and 12 injured in an accidental explosion caused by a butane gas cylinder in the Egyptian canal city of Port Said, Ahram Online said.

According to Ahram Online's reporter in the field, the gas cylinder exploded after accidently being struck by fireworks, killing 38-year-old Egyptian journalist Salah Hassan.

The explosion took place as dozens of protesters opposed to President Mohamed Morsi gathered at the city's Al-Shuhada Square in front of the governor's office.

Earlier on Friday, June 28 thousands of anti-government protesters marched to the square, chanting against both the president and the Muslim Brotherhood.

Friday witnessed nationwide protests in Egypt both for and against the embattled president, who was propelled to power by the Muslim Brotherhood in June 2012 elections.

In Cairo, hundreds of thousands gathered at Nasr City's Rabaa Al-Adawiya Mosque in support of Morsi, while thousands of anti-Morsi protesters marched to Tahrir Square to demand his ouster.