Shots were fired and security forces used tear gas during a funeral in the Egyptian city of Port Said for people killed in clashes triggered by death sentences for supporters of a local football team.
Egyptian troops were sent to the city on Saturday to quell the unrest.
Al Jazeera's Rawya Rageh reporting from Port Said said that the atmosphere was tense at the funeral march, with thousands of people chanting anti-government slogans.
A series of violent clashes continued across Egypt for a third day between protesters and riot police, after thousands of Egyptians took to the streets to mark the second anniversary of the revolution that toppled longtime leader Hosni Mubarak.
Clashes began after a Cairo court handed out 21 death sentences in connection with last year's deadly football riots in Port Said.
A US embassy spokesman in Cairo announced that the US embassy has suspended all its services and activities with the public, including issuing visas, due to ongoing clashes between anti-government protesters and security forces near Tahrir Square.
Security forces also fired teargas at protesters in the Nile Delta city of Zagazig to stop fighting between pro- and anti-government groups.
And in Suez, demonstrators set fire to a police station, expressing frustration with Mohamed Morsi, the Egyptian president, who they say failed to deliver on his economic promises.
"Until now, none of the revolution's goals have been realised," said Mohamed Sami, a protester in Tahrir Square. "Prices are going up. The blood of Egyptians [is] being spilt in the streets because of neglect and corruption and because of the Muslim Brotherhood is ruling Egypt for their own interests."
Calls for national dialogue
Ten people were killed on Friday in anti-government protests in Suez and Ismailia, and more than 470 people were wounded; Mohamed Morsi, the Egyptian president, deployed the army in Suez to restore order.
On Saturday, police again fired teargas in the city when protesters angry at Friday's deaths hurled petrol bombs and stormed a police post and other governmental buildings including the agriculture and social solidarity units.
Around 18 prisoners in Suez police stations managed to escape during the violence, a security source there said, and
some 30 police weapons were stolen.
On Saturday evening, Egypt's National Defence Council, headed by Morsi, condemned the street violence and called for national dialogue to resolve political differences, the information minister said after the council met.
Al Jazeera's Mike Hanna, reporting from Cairo, said that the meeting by the council had been "rejected by many opposition groups."
"It also said that the council reserves the right to impose states of emergency or curfews either in the whole of the country or in particular areas," said Hanna.
He added that the council's statement did not "threaten or say it was considering to do so but it [was] a thinly veiled threat that this particular body - a new one to Egyptians - could be prepared to flex its considerable muscle should the situation on the ground continue to deteriorate."