The death toll in pro-democracy protests in Egypt on Sunday climbed to 20, officials told Agence France-Presse adding that most of those killed were Islamist demonstrators.
At least 19 protesters, mostly Islamist supporters of Mohamed Morsi, Egypt's first freely elected president who was ousted by then army chief Sisi in July 2013, and a policeman were killed, a health ministry official said.
The Cairo violence accounted for all but one death, that of a demonstrator in Alexandria.
Late Sunday, officials had put the death toll at 15, including the policeman who was shot dead during clashes in a northern Cairo district.
Tensions had surged ahead of the anniversary, and a female demonstrator was killed in clashes with police during a rare leftwing protest in Cairo on Saturday.
Shaima al-Sabbagh, member of the Socialist Popular Alliance, was shot with birdshot near Tahrir Square. The alliance said she was part of a group of protestors who were carrying flowers to Tahrir Square when the shooting occurred.
An 18-year-old female protester was also killed on Friday in clashes in Alexandria.
Security forces were also dispatched to Rabaa Square in northeast Cairo on Sunday, where hundreds of supporters of Islamist President Mohamed Mursi were killed in August 2013, one month after the army toppled him.
Although a security crackdown has virtually ended street demonstrations, several took place this week in Cairo and Egypt’s second city, Alexandria.
In a televised address on Saturday, President Abdel Fattah al-Sisi praised the desire for change Egyptians showed four years ago but said it would take patience to achieve all of “the revolution’s goals.”
Sisi announced a roadmap to democracy after toppling Mursi when mass protests against his rule erupted. But human rights groups accuse the former military intelligence chief under Mubarak of restoring authoritarian rule to the most populous Arab state. The government says it is committed to democracy.
Opponents say new laws, including one restricting protests, have rolled back freedoms won in the uprising, when hundreds died as security forces clashed with protesters. Islamists and liberal activists, including many who supported removing Mursi and his Muslim Brotherhood, have been jailed.
Mubarak-era figures are slowly being cleared of charges and laws curtailing political freedoms have raised fears among activists that the old leadership is regaining influence.
An Egyptian court ordered the release of Mubarak’s sons Alaa and Gamal on Thursday pending a retrial in a corruption case, they were freed on Monday. In November, a court dropped charges against Mubarak of conspiring to kill protesters in the uprising.