Egypt's Muslim Brotherhood called for supporters of ousted President Mohamed Morsi to partake in a nationwide "millions' march of anger" Friday to protest the recent security forces' violent crackdown on protesters.
The announcement came after hundreds of people were killed when security forces cleared two pro-Morsi protest camps, ending sit-ins that began after the army toppled Morsi on July 3.
"Anti-coup rallies tomorrow will depart from all mosques of Cairo and head towards Ramsis square after Jumaa prayer in 'Friday of Anger,'" Muslim Brotherhood spokesman Gehad el-Haddad wrote on his Twitter account.
"Despite the pain and sorrow over the loss of our martyrs, the latest coup makers' crime has increased our determination to end them," the group said in a statement on Friday.
Before the Brotherhood's annoucement, Egypt's army-backed government said on Thursday it would turn its guns on anyone who attacked the police or public institutions.
The Health Ministry said that at least 578 civilians and 44 security personnel were killed in nationwide clashes on Wednesday, and more than 3,500 injured.
VIDEO: Bullets fly on Cairo streets
Officials from the Muslim Brotherhood have said the true death toll was far higher, with a spokesperson saying 2,600 people had been killed in the "massacre."
The group accuses the military of staging a coup when it ousted its leader last month. Liberal and youth activists who backed the military saw the move as a positive response to public demands.
Egypt spent its first day under emergency rule and curfew Thursday, with Cairo remaining tense and bracing for further unrest.
Military forces closed off entrances and exits and roads leading to Tahrir square with armored personnel carriers and barbed wire, in preparation for Friday protests.
Security forces also closed off all streets leading to Rabaa al-Adawiya Mosque, the site of the Wednesday crackdown.
Al Jazeera correspondent D. Parvaz confirmed that plans were moving forward for Friday's demonstrations.
The Anti Coup Alliance, which includes the Muslim Brotherhood and other Morsi supporters, called for marches from 28 mosques in Cairo. The group also called for protests and marches to main squares across the country.
While plans were being made, Morsi supporters gathered Thursday at Al Amin Mosque, two streets away from Rabaa Square, to mourn those lost on Wednesday and to vow revenge. On the other side of town, police mourned their colleagues killed during the same clashes.
Families had hoped to bury their dead on Thursday, but several of them said they were unable to acquire the proper permits. The Health Ministry wanted them to accept death certificates that said their relatives committed suicide, they said.
Police were also out Thursday removing the debris from the camps at Rabaa and Nahda, where thousands of pro-Morsi supporters were driven out and hundreds killed.
Morsi supporters remained defiant while rallies supporting the Brotherhood continued on Thursday. The headquarters of Egypt's Giza governorate was even stormed and set on fire by Morsi supporters.
The army-backed interim government has defended the crackdown on Morsi's supporters, saying authorities had no choice but to act.
Residents say they are tired of the violence.
TIMELINE: Egypt in turmoil
"We all saw that Morsi supporters were armed and were shooting at police too. Anyway, this division has to end, no more violence. We want stability," said Ahmed Zayan, another Cairo resident.
Human Rights Watch has condemned Wednesday's violence in Egypt, saying it holds the government responsible for the killings of pro-Morsi supporters in Rabaa and Nahda.
The state of emergency is set to run for a month, despite the Muslim Brotherhood calling for yet another mass demonstration on Friday.
Meanwhile, in response to the violent crackdown, President Barack Obama said in a press conference Thursday that the U.S. is canceling a bi-annual joint military exercise with Egypt scheduled for next month.
Obama said the U.S. "strongly condemns" violent steps taken by the state security forces, and called for the state of emergency to be lifted.
"We sustain our commitment to Egypt and its people ... but our traditional cooperation cannot continue as usual," the president said, announcing the cancellation of the Bright Star exercises, which typically involve several other European and Arab allies.
However, Obama did not mention any changes to the $1.3bn annual U.S. military aid package to Egypt.
Late Thursday, the military-backed interim Egyptian government released a statement saying that Obama's remarks were not based on "facts" and would only strengthen and encourage violent opposition.
Al Jazeera and wire services