By Dina Zayed and Yasmine Saleh
CAIRO (Reuters) - Egypt's military rulers urged national unity and warned of the dangers of anarchy Wednesday after 13 people were killed in the worst Christian-Muslim violence since Hosni Mubarak was toppled from power.
A new cabinet met for the first time and decided it would on Thursday redeploy the police force which largely disintegrated in the first days of the uprising that swept Mubarak from the presidency and left the military in control.
The Health Ministry said 13 people were killed and 140 wounded in sectarian violence Tuesday ignited by tensions that have built up since an arson attack on a church south of Cairo Saturday.
The strife poses another challenge to the Supreme Council of the Armed Forces which has been governing with a depleted police force and wants to hold elections within six months so it can relinquish power.
In a meeting with members of the cabinet, the military council urged citizens to unite and warned against chaos "which threatens national security, especially with the existence of foreign forces targeting the country's stability and security."
The state news agency did not elaborate on the council's reference to foreign threats, but said the meeting had addressed "sectarian strife" and its impact on the nation and economy.
Egyptians took pride in the Christian-Muslim solidarity displayed during the revolution that toppled Mubarak on February 11 and hoped the uprising had buried tensions that have flared up with increasing regularity in recent years.
It was not clear how many of the dead from Tuesday's violence were Christian or Muslim. The trouble had started on a Cairo highway where Christians had been protesting over the arson attack on the church south of the capital.
The Muslim Brotherhood, an Islamist group and Egypt's best organized political force, warned of attempts by remnants of Mubarak's regime "to ignite strife in these delicate circumstances."
Brotherhood leader Mohammed Badie called on Egyptians to stand in "one line to support the armed forces and the cabinet so they will be able to realize the demands of the revolution."
Hundreds of people faced off in the violence, hurling petrol bombs and rocks, witnesses said. Injuries included head wounds, bullet wounds and broken limbs, the state news agency quoted a senior Health Ministry official as saying. At least one of the dead, an 18-year-old Christian, had been shot in the back.
It was not clear who had opened fire. The military, trying to restore order, had opened fire in the air at one point.
"The supreme military council, the government and civil society must react because we do not want this to escalate and I fear we may return to the dark tunnel of sectarian tension," said Amr Hamzawy, an analyst and part of the reform movement.
The attack on the church was triggered by a family dispute over a romance between a Muslim woman and a Christian man. Similar stories have triggered strife in the past.
Hundreds of Christians have been protesting outside the Cairo headquarters of state television since the arson attack.
Seeking to contain tensions, Field Marshal Mohamed Hussein Tantawi, head of the military council, has said the military would rebuild the church before Easter.
The Coptic Church, which represents the minority Christian population, issued no comment on the violence and a church official declined to speak about it. In the past, the church has urged calm after such violence.
"The system now does not have the strength or the authority or even the military power to separate Muslims and Christians, if, God forbid, there are further implications," political analyst Diaa Rashwan said. "The system does not even have the power to ease traffic," he added.
New Interior Minister General Mansour el-Essawy said his main priority is to redeploy police forces across the country.
The revolutionary groups which rose up against Mubarak have demanded a major shake-up of the security forces, including the dissolution of an internal security agency with a reputation for human rights abuses and spying on citizens.
Amnesty International condemned what it described as the army's heavy-handed actions to clear Tahrir Square of protesters Wednesday, saying soldiers beat demonstrators and made scores of arrests.
Witnesses said men in plain clothes had hurled stones at a few hundred people gathered in the square which had been the epicenter of the protest movement against Mubarak.
The military council has scheduled a referendum on constitutional reform for March 19. The amendments will open the way to elections for the presidency and parliament, after which the military says it will hand power to a civilian government.
(Writing by Tom Perry; Editing by Janet Lawrence)