The Health Ministry announced 18 deaths on the fourth anniversary of the January 25 revolution, 16 of which occurred in clashes between protesters and police in Matareya, Haram and Alexandria.
At least 52 were injured nationwide, including five police officers.
An Interior Ministry spokesperson told the state-owned Middle East News Agency that 150 protesters were arrested across the country. The ministry claimed many were supporters of the Muslim Brotherhood, according to the state-owned Al-Ahram newspaper.
Muslim Brotherhood-affiliated social media accounts posted pictures of bloody-faced protesters, asserting that the casualties were peaceful demonstrators attacked by police forces.
The Interior Ministry announced the killing of an armed man in Alexandria earlier on Sunday, who they claimed was one of two civilians using automatic weapons to shoot randomly at protesters.
The Middle East News Agency reported the death of two people who they said were attempting to install a bomb at an electricity tower in Beheira.
Clashes broke out in downtown Cairo between dozens of protesters and a group of civilians in front of the Journalists Syndicate on Sunday afternoon. Police forces dispersed protesters and began to round them up and make a number of arrests.
A Mada Masr reporter said a march left from the syndicate heading down Ramses Street in downtown Cairo. It was a peaceful demonstration, with protesters chanting slogans.
At around 4.30 pm, the march came under attack. Police fired tear gas canisters at demonstrators, while people in civilian clothes threw stones from within and behind police lines.
The reporter witnessed demonstrators being grabbed by police, but was unable to confirm whether or not they were arrested.
Eyewitness Shady Hussein said the clashes started when supporters of President Abdel Fattah al-Sisi intervened in the protest and raised posters of the president, throwing rocks at protesters.
The Association for Freedom of Thought and Expression (AFTE) said in a report released Sunday that nine journalists were briefly arrested while covering events. Some of them, including a Dutch journalist, were reportedly assaulted by police forces who confiscated their equipment.
BBC journalist Orla Guerin said security forces threatened to shoot her if she didn’t stop filming protests in Ain Shams. Al-Fagr journalist Sarah Hisham was beaten by civilians while covering protests in Ramsis street, and Nader Nabil was shot with pellets in the head and hands, AFTE reported.
Dozens also marched in a protest in Maadi organized by revolutionary forces, which ended peacefully, eyewitnesses recounted.
The Ministry of Interior dispersed protests in October 6 City and Maadi using tear gas, according to several media reports.
Security forces closed off Tahrir Square and dispersed small attempts at protests on its peripheries throughout Sunday. Small groups of pro-Sisi protesters were reportedly asked politely by police to move elsewhere.
An April 6 Youth Movement spokesperson told privately owned Al-Shorouk newspaper that the movement was planning to commemorate the revolution with marches. He said five members were arrested in downtown on Sunday by officers in civilian clothing.
Amongst the fiercest clashes in Cairo on Sunday were those around the northern district of Matareya. This working-class neighborhood witnessed ongoing violence between opposition forces and supporters of ousted President Mohamed Morsi and police and civilian supporters of President Sisi.
The death toll and number of arrests in Matareya were reported to be amongst the highest in Cairo.
At around 5 pm, hundreds of protesters reportedly pushed riot police troops out of Matareya Square. Clashes centered around Taawon Street leading up to the square. Photos and videos reveal rock-strewn streets and troops firing tear gas at protesters from armored personnel carriers.
Private media outlets Al-Shorouk, Al-Masry Al-Youm, Veto, and Al-Mogaz reported that Morsi supporters set fire to tires in the square after pushing Central Security Forces back to the nearby Matareya Police Station and sealing off the streets surrounding the square.
Protesters could be heard chanting slogans against Sisi, the police and the Armed Forces.