Opponents of Egypt's President Mohammed Morsi clashed with police near Cairo's Tahrir square on Sunday, with protesters throwing stones whilst the police retaliated with tear gas.

Hundreds of protesters staging a sit-in in Tahrir have vowed not to leave before Morsi rescinds his decrees.

"The position is obvious, there is no negotiation," said Nagy Soliman, a member of the Al Masreyeen al Ahrrar party, as he took part in the protest on Tahrir square.

"The political powers will not meet with President Mohammed Morsi, until he has cancelled the constitutional declaration."

Morsi's edicts place him above oversight of any kind, including that of the courts.

He extended the same protection to two key bodies dominated by his Islamist allies: parliament's upper chamber and a panel tasked with drafting a new constitution.

Meanwhile, hundreds of his supporters gathered outside of Al Nasr mosque in El-Arish, North Sinai, to show their support for Morsi.

Supporters insist that the measures were necessary to prevent the courts, which already dissolved the elected lower house of parliament, from further holding up moves to stability by disbanding the assembly writing the new constitution, as judges were considering doing.

Supporters and opponents of Morsi have grown more entrenched in their potentially destabilising battle over the Islamist leader's move to assume near absolute powers, with neither side appearing willing to back down as the stock market plunged amid the fresh turmoil.

The two sides also have called for massive rival protests Tuesday in Cairo, signalling a protracted struggle.