At least 15 Egyptian policemen were killed during clashes with protesters supporting  deposed President Mohammed Morsi, Al Arabiya’s correspondent reported while Agence France-Presse reported that at least eight protesters were killed on Friday in the Egyptian Mediterranean town of Damietta in clashes with security forces.
Also, four Morsi loyalists were killed in clashes with security forces in the Suez Canal city of Ismailiya, AFP reported a security official as saying.
Violence has been reported elsewhere  in the country. In an armed attack on a Cairo checkpoint, one policeman was killed while in al-Arish in north Sinai, an Al Arabiya correspondent reported that one soldier was killed and another was injured after an attack by gunmen.
Tear gas was fired and shooting was heard on Friday at the main Cairo square where thousands of Morsi supporters were protesting against a bloody crackdown  on Islamists on Wednesday that killed more than 600 people, a Reuters witness said.Two witnesses said they saw protesters throw petrol bombs at a police station near the square.
Meanwhile, the Egyptian military is deploying to guard “vital installations,” Reuters reported the state media as saying, as Morsi supporters chanted “down with military rule.”
In the northern city of Tanta, Egyptian security forces fired birdshot and tear gas to block Morsi loyalists from reaching a government building, AFP reported Friday.
Egypt’s Islamists called for a “Friday of anger ” in Cairo to express their disdain of the security crackdown against their sit-ins in which at least 623 people have been killed, according to Reuters.
“Anti-coup rallies... will depart from all mosques of Cairo and head towards Ramsis square after [traditional Friday] prayer in ‘Friday of Anger’,” AFP quoted the Muslim Brotherhood spokesman Gehad al-Haddad as saying via his Twitter account.
“After the blows and arrests and killings that we are facing, emotions are too high to be guided by anyone,” Reuters quoted Haddad as saying.
He added: “Despite the pain and sorrow over the loss of our martyrs, the latest coup makers’ crime has increased our determination to end them.”
Ahead of the Friday protests, a blast has targeted a railway connecting the Alexandria and Marsa Matrouh provinces in Egypt, Al Arabiya's correspondent reported.
Meanwhile, the United Nations urged for “maximum restraint”  from all sides as death toll climbed during events on Wednesday when police cleared out two protest camps in Cairo setup to denounce the military overthrow on July 3 of Egypt’s first freely elected president, Morsi.
Unaffected by criticism from major Western allies and the United Nations, Egypt’s army-backed government continued to warn that it will turn its guns on anyone who attacked the police or public institutions after protesters torched a government building in Cairo on Thursday.
On Thursday, at least seven soldiers and a policeman were killed in the Sinai Peninsula and another police officer killed in the central city of Assiut.
The call for new protests sounds the alarm for renewed violence. Wednesday’s crackdown was Egypt’s bloodiest day since the the 2011 uprising against autocrat Hosni Mubarak .