Thousands of demonstrators waved red cards in Tahrir Square on Sunday to demand the resignation of Egypt's Islamist President Mohammed Morsi, as the spirit of 2011's revolution returned to the iconic Cairo protest venue.

Protesters chanted "The people want the ouster of the regime!" - the signature slogan of the uprising that ousted Hosni Mubarak and brought Morsi to power.

Jubilant men, women and children brandished red cards, blowing whistles and vuvuzelas and chanting, "Leave, Morsi!"

On the other side of Cairo, thousands of the Islamist leader's backers gathered not far from the presidential palace in a show of support.

The demonstrations on Sunday, the anniversary of Morsi's inauguration as Egypt's first freely elected leader, are the culmination of growing polarization since he took office.

"This is the second revolution and Tahrir is the symbol of the revolution. The revolution will be launched from here," said Ibrahim Hammouda, a carpenter who had came from the northern city of Damietta to join the protests.

In 2011, when hundreds of thousands of people took to the streets to end Mubarak's three-decade rule, they held up posters of government figures with their faces crossed out.

This time, protesters are holding pictures of senior leaders of the Muslim Brotherhood, from which Morsi hails.

Morsi was elected a year ago in Egypt's first free vote. Today, his critics accuse him of betraying the revolution by concentrating power in the hands of Islamist groups.

They accuse him of breaking his promise to be a president "for all Egyptians" and letting the economy dive into free fall.

"I'm here because Morsi, who I voted for, betrayed me and did not keep his promises. Egypt will be liberated again from Tahrir Square," said Mohammed Samir who traveled from the Nile Delta city of Mansura.

The Tahrir protest began hours before scheduled rallies and marches due to begin at 5 pm, with several hundred people having spent the night in the square.

On the outskirts of the square, security checkpoints were manned by protesters in fluorescent vests under signs reading: "No entry to the Brotherhood".

"We are protecting the revolution from those who are against the revolution," said protester Essam Ahmed.

Meanwhile, pro-Morsi supporters insist that ousting an elected president would be a coup against democracy that they will not allow.

Egypt is deeply divided between Morsi's mainly Islamist supporters and a broad-based opposition that also includes many deeply religious Muslims.

The Muslim Brotherhood was long banned under Mubarak's rule, but since the uprising they have dominated parliament, drafted a controversial constitution and been given key cabinet and local government positions.

AFP-AP