As Islamist forces stage a rally in support of President Mohamed Morsi in Cairo's Nasr City, Morsi's opponents are calling on him to step down in the city's central Tahrir Square.

Thousands of people marched on Friday towards Tahrir Square, chanting against Morsi and the Muslim Brotherhood.  Marches in Cairo originated from Mostafa Mahmoud Square, Sayeda Zeinab, Al-Azhar Mosque and Shubra.

Similarly, in the Mediterranean city of Alexandria, hundreds of opposition supporters are marching from the centrally-located Al-Qaed Ibrahim Mosque and from the eastern Dawaran Jihan area en route to the upscale Sidi Gaber district.

Dozens of protesters are waving Egyptian flags and anti-Brotherhood placards along the city's corniche. Others are holding up red signs reading "leave."

The demonstrations were called for by the newly-created 30 June Front under the slogan "leave." These efforts are in preparation of the anticipated demonstrations on Sunday which will demand for the president's resignation and early presidential elections.

The Front's call was supported by several opposition groups, including the Egyptian Popular Current, who published a map of their planned protests on Friday covering governorates such as Sharqiya, Gharbiya, Qalioubiya and Assiut.

On Thursday, protesters began a sit-in at Tahrir Square to demand Morsi's removal. As in Alexandria, protesters are raising red "leave" signs.

Some 32 tents were pitched in the middle of the square on Thursday morning, and four others were erected near the Egyptian Museum, state news agency MENA reported.

Thousands of protesters descended on the flashpoint square late on Wednesday where big screens had been set up ahead of President Morsi's speech.

Angry protesters chanted against the president and the Brotherhood. Others held aloft shoes and red cards as a sign of their contempt.

Morsi's three-hour speech on Wednesday offered limited concessions and called for national reconciliation but was not well-received by the opposition.

Tensions have been building between opponents and supporters of the president after clashes in several governorates – including Daqahliya, Sharqiya and Zagazig – left three dead and scores injured in the past week.

Meanwhile, Islamist forces, including the Brotherhood's Freedom and Justice Party, are holding a rally at Cairo's Rabaa Al-Adawiya Mosque in support of Morsi's presidential "legitimacy."  The rally, beginning on Friday, is expected to extend into a sit-in.