(CNN) -- Friday is a revered day on the Egyptian calendar, increasing the fervor for another day of rallies and possible confrontations between the interim government and backers of deposed President Mohamed Morsy.
Both sides called for Tenth of Ramadan demonstrations in the streets of the capital of Cairo. Ramadan's 10th day in October 1973 marked the beginning of a war with Israel that is remembered with pride in Egypt.
Supporters of Morsy, who is backed by the Muslim Brotherhood, announced a "Breaking the Coup" rally. Morsy's opponents called on people to turn out to support the new government and protest "against terrorism."
Dozens have been reported killed and thousands injured in protests since Morsy was forced out and arrested by the Egyptian military on July 3. Amid fears of widening violence, interim President Adly Mansour took a hard line Thursday in his first televised speech.
"We will battle to the end to bring security. We will maintain the revolution. The past will not return," vowed Mansour, a judge installed by the military pending a promised return to democracy.
The military issued its own warning to demonstrators "not to deviate from peaceful means of expression." The statement, released to the state-run al-Ahram Online news agency said, "Whoever does not abide peacefully is only exposing his life to danger and will be dealt with according to the law."
Human rights groups have accused the military of heavy-handed dealings with protesters, while others have blamed Morsy's supporters and opponents for inciting violence.
The U.S. Embassy in Cairo warned Americans to limit travel there during Friday's protests.
Also on Friday, Morsy's Freedom and Justice Party accused the interim government of illegally transferring detainees who belong to the party.
The arrests this month of eight leading Freedom and Justice figures were politically motivated and illegal, making their transfer to a heavily guarded prison illegal, too, the party says. Human rights organizations have backed the political motivation claim.
Among the detainees were Mohamed Mahdi Akef, former supreme guide of the Muslim Brotherhood; Dr. Saad Al-Katatni, chairman of the Freedom and Justice Party; Khairat Al-Shater, deputy to the supreme guide; and Sheikh Hazem Salah Abo Ismael.
CNN's Salma Abdelaziz contributed to this report.