The Egyptian army stationed soldiers on the streets of the coastal city early Saturday morning. A few hours prior to the deployment, at least six people were killed there during clashes between police and opponents of President Mohammed Morsi. Initial reports did not indicate the number of troops sent into the city to restore peace.

Throughout the day on Friday, thousands of people took to the streets across Egypt to mark the second anniversary of the day when protesters began the uprising in Tahrir Square, which eventually led to the downfall of former President Mubarak.

Medical sources said that at least 476 people were injured in Friday's demonstrations.

In the wake of the turbulence, Morsi released a statement on his Twitter site, asking Egyptians to "adhere to the noble principles of the Egyptian revolution in expressing opinion freely and peacefully."

He had expressed a similar sentiment in a speech the day before, which had gone unheeded. Instead, protesters heard the call of opposition leaders who had asked them to express displeasure with the government of President Morsi, a former member of the Muslim Brotherhood who is backed by the Islamist movement.

"Go out into the squares to finally achieve the objectives of the revolution," one opposition leader, the former International Atomic Energy Agency chief, Mohamed ElBaradei, said via the microblogging website Twitter.

In Cairo, police fired tear gas into crowds of protesters who had pelted them with rocks or petrol bombs, as well as a group descending upon the presidential palace. Elsewhere in the capital city, there were reports of Morsi opponents blocking roads and metro stops.

Protesters singled out government buildings in other cities, as well. In Alexandria, police were reported to have clashed with protesters who had attempted to attack a local municipal building.

In the coastal city of Islamilia, Morsi opponents attacked the local Muslim Brotherhood office.

The Muslim Brotherhood kept a low profile on the anniversary, calling no rallies of its own but instead announcing a charitable and social initiative it dubbed "Together we will build Egypt."

The violence first broke out on Thursday when a group of protesters approached a cement wall erected to protect government buildings in Cairo.

Although Morsi is the country's first democratically elected president, he has not won the trust of his opponents. Most recently, he incited the ire of the opposition when he attempted to expand his powers with a presidential decree so that he could hold a referendum on Egypt's new constitution. After voters approved the constitution, he relinquished the extra powers.

The opposition rejects the constitution in its current form, arguing that it does not provide sufficient protection for human rights.

kms/jm (Reuters, AFP, dpa)