At least 53 people were killed in clashes between supporters of the Muslim Brotherhood and police in Egypt, as thousands of the military's supporters marked the anniversary of the 1973 Arab-Israeli war.
Loyalists of deposed President Mohamed Morsi, overthrown in a July military coup, tried to converge on Cairo's Tahrir Square for the anniversary celebrations on Sunday, when police confronted them.
At least 46 people were killed in Cairo and at least five others south of the capital, while another 268 people were wounded across Egypt, a spokesman of the Health Ministry said.
Mostafa Ramadan, an anti-coup protester and student at Al-Azhar University in Cairo, suffered injuries to the head after being hit by a rock and was struck in the hand with birdshot.
"We were walking peacefully in the march from Mohandesseen area, in Giza, when we found police forces waiting for us under the bridge," he told Al Jazeera’s correspondent, who cannot be named due to security reasons.
"We kept saying we are peaceful, but they cursed us and started firing tear-gas bombs on us and live ammunition," Ramadan said.
Sunday's death toll was the highest in clashes between Brotherhood supporters and police since several days of violence starting on August 14 killed more than 1,000 people.
An Interior Ministry statement said police arrested 423 protesters in Cairo, accusing them of vandalism and "firing live rounds and birdshot".
Three months after Morsi's overthrow, followed by a harsh crackdown on his Muslim Brotherhood, the protesters had planned to galvanise their movement in a symbolic attempt to reach Tahrir Square.
Hundreds of thousands of people had filled the square in February 2011 to force President Hosni Mubarak to step down, and again in July 2013 to urge the army to depose his successor Morsi.
But on Sunday, security forces guarded entrances to the square, frisking people arriving for the anniversary celebrations.
Several thousand people, some carrying pictures of army chief Abdel Fattah el-Sisi, waved Egyptian flags as warplanes flew overhead in formation and patriotic songs blared from loudspeakers.
Sisi, flanked by interim president Adly Mansour and Jordanian Prime Minister Abdullah Nsur, attended a fireworks display in a military stadium, followed by a long song-and-dance show.
"The army, police and the people are together hand in hand... We will protect Egypt, the Egyptian people and the will of Egyptians," Sisi told the gathering amid loud cheers.
Earlier in Cairo, the air was thick with tear gas and the crackle of gunfire as police confronted several marches heading for Tahrir.
Call for more protests
Prime Minister Hazem el-Beblawi urged Egyptians to unite, saying the country is on the road to recovery.
Follow our ongoing coverage of the political crisis in Egypt
"As we go through these critical times all Egyptians should stand together, be confident and be optimistic about the future," he said in a televised address.
The Anti-Coup Alliance called for more protests this week and specifically urged students across Egyptian universities and schools to protest on Tuesday "against these continuing massacres".
"The alliance holds coup authorities and the military-appointed government fully responsible for all the blood of Egyptians being spilt right now, and for every Egyptian killed on this day," it said in a statement.
Morsi's opponents demonstrated in their millions in June and July to urge the army to remove him, accusing the Islamist of failing the revolution that brought him to the presidency and concentrating power in the hands of his allies.