Seven reported dead and scores of civilians and security forces injured as thousands protest for anti-Morsi protests

Fatal clashes continued into the night in several Egyptian cities on Friday as thousands of demonstrators took to the streets to protest against President Mohamed Morsi, the Muslim Brotherhood, and police brutality – exactly two years after the start of the 2011 revolution that toppled Hosni Mubarak.

According to state media, at least seven people died in Suez and 379 were injured across the country as riots broke out in Cairo's Tahrir Square and cities including Alexandria, Mahalla, and Ismailia. Police repeatedly fired teargas across much of central Cairo and protesters pelted them with stones – bringing parts of the city's road and metro networks to a standstill.

As night fell, medics warned that the amount of teargas in Tahrir Square had reached a "dangerous level". According to Tahrir Bodyguards, a group protecting female protesters, at least nine women were sexually assaulted in the square – prompting memories of some of the worst moments of the Egyptian uprising in 2011.

For many on the streets, there was a painful sense of deja-vu. "There's no military dictatorship any more, but there are the beginnings of a theocratic one," argued Karim Abadir, a co-founder of the Free Egyptians – a liberal opposition party – who had set up a tent in the centre of Tahrir Square.

Hisham Abdel-Latif, another protester who took part in one of several feeder marches that snaked their way towards Tahrir from the Cairene suburbs, said Egyptians were "now ruled by a gang that is exactly the same as the Mubarak gang, except they now have beards".

Violence broke out in Cairo in the early hours of the morning, as police burnt down two tents in Tahrir Square. For much of the day, police and hundreds of protesters then took it in turns to lob chunks of rubble over two makeshift walls built to protect the interior ministry from attack.

One of the stone-throwers, Karim Ali, said it was revenge for the protesters killed by police since 2011. "The police are behaving the same as they did during the Mubarak years," he said.

Morsi may be Egypt's first democratically-elected president, but many Egyptians fear he only has the interests of Islamists at heart.

In particular, the opposition was incensed by the way he bypassed judicial protocols in November to push through a new constitution that the left sees as the first step towards Islamic law. In his defence, Morsi's allies claimed it was a clumsy but well-meant attempt to create longterm democratic stability.

Many also blame Morsi for failing to tackle Egypt's creaking infrastructure – more than 70 Egyptians have died in train accidents since December – and its dire economic predicament: Egypt's foreign reserves have fallen drastically in recent weeks.

"I'm here to get rid of Morsi," said Moustapha Magdi, an unemployed commerce graduate on a march from Giza. "First Mubarak, then Tantawi, now Morsi. We are only ruled by bastards."

Magdi criticised Morsi's failure to prosecute members of the military who killed Egyptians during and since the revolution.

"Where are these people? They are outside. They are not in prison. There is no justice," he said.

According to a recent poll, Morsi's approval ratings rose to 63% in January, and even some protesters were ambivalent about blaming the president himself for the problems besetting Egypt.

"Morsi has not been given a chance," said El-Sherbeeni Ahmed Mohammed, a retired financial consultant. "A barren patch of land must be given time to become fertile."

"The protests, it's too much. It's stopping the tourists," said Mohammed Gooda, a 43-year-old taxi driver who claimed the constant political instability wasdamaging business. Tourism is down by 22% since 2010. "For people like me, the constitution is not very important. It is more important that we work and we feed our families."

Marching from Giza, 20-year-old Moustapha el-Nahaal gave Morsi his backing, and instead blamed his technocrat ministers. "I want [prime minister] Hisham Qandil to go, along with all his team," said el-Nahaal, a 20-year-old commerce student and an activist for Strong Egypt, a moderate Islamist party.

"I'm supporting Morsi," says 65-year-old Hossam El-Deeb, a bearded mosque official, a former political prisoner under Mubarak. "The revolution has achieved a lot in psychological terms," he added, suggesting that it was too early to criticise Morsi for Egypt's dire economic predicament.

A spokesman for the Muslim Brotherhood said that violent protests were unconstructive at a time when the country needed to pull together. "The country is dying because of malpractice over 30 years of Mubarak's dictatorship," the Brotherhood's Gehad al-Haddad told the Guardian. "Now we have to co-operate, or continue falling down."

Elsewhere in Cairo, protesters and supporters of the regime clashed outside an office of the Muslim Brotherhood. There were also clashes in Alexandria, Port Said, and outside the presidential palace in Heliopolis.