CAIRO // Protesters lobbed molotov cocktails and shot fireworks over the walls of the presidential palace amid clashes with police last night as Egypt descended into more turmoil.
President Mohammed Morsi responded by warning that security forces would "act with utmost decisiveness" to protect state buildings.
Mr Morsi said on Facebook that he would hold opposition groups behind the violence "politically accountable".
He said protesters had tried to break down gates and scale palace walls. He ordered opposition groups to denounce the violence and call on followers to withdraw.
Police, some in armoured personnel carriers, fired tear-gas canisters to disperse crowds outside the palace as young men responded with rocks and rockets into the night.
Some men in bandanas grabbed the canisters and threw them over the palace walls, where a fire truck was spraying water on small fires.
The escalation came after demonstrations by thousands across the country in what some dubbed the "Friday of Deliverance".
In the Red Sea cities to the east, including Port Said, Ismailia and Suez, many said they were mourning the loss of dozens of Egyptians who died during clashes with police over the past nine days.
In Port Said, the city that saw the worst violence in the latest unrest, the atmosphere was defiant, with some openly calling for secession from the state. Thousands gathered in front of Mariam mosque to chant against Mr Morsi's regime.
In Alexandria, protesters blocked streets and train tracks with barricades made of bonfires and rubbish bins. There were chants of "Down, down, with the rule of the [Muslim Brotherhood's] supreme guide. Down, down with Morsi. Leave, we are poor people," the state-run Al Ahram newspaper reported.
Violence broke out on January 25, the two-year anniversary of the uprising that toppled the regime of Hosni Mubarak and paved the way for Mr Morsi to win the country's first democratic presidential elections in June.
Many Egyptians feel increasingly disenfranchised by Mr Morsi because of the perception that he is allowing the Muslim Brotherhood to spread its members throughout the government.
And when a judge last week announced death sentences for 21 defendants over a riot in a football stadium in Port Said a year ago today, it set off battles and angry attacks on police and prison buildings.
Nearly 60 people have been killed, many of them shot, in protests since January 25. Mr Morsi responded by declaring a month-long state of emergency in the Suez Canal cities.
Adding to the ire of protesters is a worsening economic situation.
In a survey of 1,680 households in September, the Egyptian Food Observatory found 86 per cent of respondents saying their income was not enough to afford food. Unemployment has risen to 12.8 per cent.
Yesterday's protests and clashes suggested that Egypt's opposition forces, united under the National Salvation Front, may not be able end the cycle of violence even if they wanted to.
Many groups signed an agreement disavowing violence on Thursday in crisis talks initiated by Sheikh Ahmed Al Tayyeb, the head of Al Azhar - Egypt's 1,000-year-old mosque and university.
Opposition leaders have said they condone only peaceful protests, and have blamed the country's security apparatus for the violence.
"We brought down the Mubarak regime with a peaceful revolution and are determined to realise the same goals in the same way, regardless of the sacrifices or the barbaric oppression," wrote Mohamed ElBaradei, the head of the Dostour party and a senior member of the National Salvation Front.
The tirade of abuse against the Muslim Brotherhood has pushed the group into defensive mode. Mohamed Badie, the Supreme Guide of the Brotherhood, said the instability over the past week and a half was due to "regional and international forces which aim for instability and to stir up problems and ignite strife to damage Egypt ... to thwart the democratic transition".
Mr Morsi has called for national dialogue, but he was refused by opposition groups unless he appointed a unity government and agreed to amend the country's month-old constitution that passed in a public referendum despite strong disagreement from many groups.
Last week, Egypt's top general warned that "the continuation of the struggle of the different political forces … over the management of state affairs could lead to the collapse of the state".
* With additional reporting from Reuters and Agence France-Presse