Protesters in Cairo are preparing to hold another mass rally to demand that Egypt's military rulers step aside.
The demonstrators are demanding the postponement of parliamentary elections due to start on Monday.
The previous military-appointed civilian cabinet resigned earlier this week in the wake of violent protests in the capital and other cities.
State media has reported that Egypt's army appointed ex-Prime Minister Kamal Ganzouri to form a new government.
The Supreme Council of the Armed Forces (Scaf) is overseeing a transition to civilian rule following the ousting of President Hosni Mubarak in February.
Despite promises by the council to speed up the process, many Egyptians fear they intend to cling to power.
Yet many Egyptians want the elections to go ahead unhindered. The main opposition group, the Muslim Brotherhood - which is expected to do well in the planned polls - is not supporting the protests.
The news of the reported appointment of Mr Ganzouri - who headed Egypt's government from 1996 to 1999 under Mr Mubarak - has not been welcomed by the protesters.
"For the second time, we are going to depend upon the old guard of Mubarak's regime. Why we do not give chance for the young, instead of those people who are 80 years old?" one man in Cairo's Tahrir Square, Suhir Nadim, told Reuters news agency.
"Appointing Ganzouri is a crisis for the revolution. We must remain in Tahrir," another protester, 44-year-old Hossam Amer, told Reuters.
Activists, many of whom spent the night in the square, are calling Friday "the last chance" for Egyptians to demand an immediate transfer to civilian rule.
The Egyptian Independent Trade Union Federation called for a march to Tahrir Square while another labour rights group called for a general strike to back the protests.
The health ministry said 41 people had died in the violence, state television reported early on Friday.
The military council has offered its condolences, as well as compensation to families of the dead.
"What we want to hear is when they are leaving," protester Khaled Mahmoud told the Associated Press news agency.
Much of the violence has taken place in a street leading from Tahrir Square to the interior ministry. Soldiers have now set up barricades of cement, metal bars and barbed wire to separate protesters and security forces.
A media watchdog group has recommended that news outlets should temporarily stop sending women to Egypt, after two reports of sexual assaults on female journalists.
Reporters Without Borders said a French journalist was the latest victim, attacked on Thursday while she worked in Cairo.
State newspaper al-Ahram said on its website that Mr Ganzouri, 78, had agreed in principle to lead a "national salvation government" after meeting Field Marshal Mohamed Hussein Tantawi, the head of Scaf.
Mr Ganzouri, who distanced himself from Mr Mubarak's regime, has been suggested as a possible presidential candidate.
During his term as prime minister, he was known as the "minister of the poor" because he was seen as representing the less well-off, and he remains popular with many Egyptians, the BBC's Yolande Knell says.