Supporters and opponents of Egyptian Islamist President Mohamed Morsi took to the streets on Friday for rival protests a year after his election, as deadly clashes in Alexandria raised fears of widespread unrest.
Fervent displays of emotion on both sides underline the bitter divisions sweeping Egypt, with Morsi's opponents accusing him of hijacking the revolution and his supporters vowing to defend his legitimacy to the end.
One person was killed and at least 70 injured in second city Alexandria, state media reported.
Television footage showed protesters running in several directions in the city's Sidi Gaber area as gunshots were heard.
The offices of the Freedom and Justice Party, political arm of Morsi's Muslim Brotherhood, were torched in Alexandria and in Aga in the Nile Delta province of Daqahliya, security officials said.
At least four people have also died since Wednesday in clashes in the Nile Delta -- three in Mansura city and one in Zagazig, medics said.
Overnight violence also erupted in the eastern part of the Delta, north of the capital, Morsi's own home province of Sharqiya.
The unrest is seen by many as a prelude to mass anti-Morsi protests planned for Sunday, the first anniversary of his becoming president.
In Cairo, tens of thousands of Islamists gathered under the slogan "legitimacy is a red line", referring to Morsi's insistence that he has a popular mandate.
"People must go with everything they've got to defend legitimacy and Egypt," one speaker told the cheering crowd, while also urging them to keep their protests peaceful.
Meanwhile, anti-Morsi protesters joined hundreds camped overnight in Tahrir Square, epicentre of the 2011 revolt that toppled Hosni Mubarak and catapulted Morsi to the presidency.
Thousands more anti-Morsi protesters demonstrated across Cairo including in the Shubra, Sayeda Zeinab and Mohandesseen districts.
Outside the capital, his opponents gathered in Alexandria, Mansura and the canal city of Port Said.
The June 30 protest was called by Tamarod (Arabic for Rebellion), a grassroots movement which says it has more than 15 million signatures for a petition demanding Morsi's resignation and a snap election.
The broad-based opposition alleges that Morsi reneged on his promise to be a president for all Egyptians and has failed to deliver on the uprising's aspirations for freedom and social justice.
Germany warned that Egypt's fledgling democracy faces a "moment of truth", and urged Morsi to implement reforms.
Foreign Minister Guido Westerwelle said demonstrators had a right to peaceful assembly, but urged both sides to avoid bloodshed.
"This is in his view a key moment of truth for political change in Egypt," Westerwelle's spokesman told reporters.
Morsi himself warned in a televised speech on Wednesday that the growing polarisation threatens to "paralyse" the country.
He pledged to consider constitutional reforms and appealed to the opposition to join talks.
It was his latest attempt to strike up a dialogue between political factions in a country deeply split between his Islamist allies and an opposition of leftists, liberals, Christians and some Muslim groups.
On Thursday, the opposition National Salvation Front coalition rejected his offer of talks and renewed its call for a snap presidential election.
Since taking office last June 30, Morsi has squared off against the judiciary, media, police and even artists.
But he has also admitted to failings.
"I have made many mistakes, there is no question. Mistakes can happen, but they need to be corrected," he said.
He also warned the media against abusing freedoms won in the uprising.
Judges on Thursday slapped a travel ban on Mohammed al-Amin, the owner of private television channel CBC that hosts a popular satire show. He faces charges of tax evasion.
In Wednesday's speech, Morsi named him and several other private television station owners.
The army, which oversaw the transition from Mubarak's autocratic rule but has been on the sidelines since Morsi's election, warned it would intervene if violence erupts.
It has brought in reinforcements to key cities, security officials said.
In Cairo, residents were withdrawing cash and stocking up on food, and many companies plan to close on Sunday, the first day of the working week.
Fuel shortages have seen drivers queueing outside petrol stations through the night, bringing parts of the capital to a standstill.