Clashes between Muslims and Christians in Egypt left 13 dead and 140 wounded, deepening a sense of chaos as the police and ruling military struggled to maintain order barely a month after a popular uprising ousted longtime leader Hosni Mubarak.
In a sign of how much security has broken down, the pitched battles _ the deadliest in years _ went on for nearly four hours Tuesday night as both sides fought with guns, knives and clubs. Army troops fired in the air to disperse the crowds to no avail.
The new Cabinet sought to reassure Egyptians on Wednesday night, ordering police to immediately take back the streets.
The spasm of violence offered a glimpse of what has gone wrong in a one-time police state that now finds itself with less than half of its security forces back to work and a military that does not have enough troops on the ground.
The fighting began when a Muslim mob attacked thousands of Christians protesting the burning last week of a church in Soul, a village just south of Cairo.
The Muslims torched the church amid escalating tensions over a love affair between a Muslim woman and a Christian man. The relationship set off a violent feud between the couple's families. The woman's father and a cousin of the man were killed.
At one point in the battles, Christian protesters blocked a vital highway, burning tires and pelting passing cars with rocks.
Security officials said seven Christians and six Muslims were killed. The wounded were 72 Muslims and 68 Christians, according to the officials, who spoke on condition of anonymity because they were not authorized to speak to the media.
Troops later arrested 20 people, they said.
Even before the uprising that toppled Mubarak, tensions had been growing between Christians and Muslims.
The Coptic Christian minority makes up 10 percent of Egypt's 80 million people and complains of widespread discrimination that they say relegates them to second-class citizen status.
A Jan. 1 suicide bombing outside a Coptic church in the port city of Alexandria killed 21 people, setting off days of protests. Barely a week later, an off-duty policeman shot and killed a 71-year-old Christian man, and wounded his wife and four others.
Last November, police halted construction of a church, and Christians clashed with the authorities. Two Christians were killed and 68 people were hurt in the fighting.
Sworn in Monday, Prime Minister Essam Sharaf and his government issued a statement Wednesday saying security forces would return "in full force to carry out its national duties."
The statement also appealed to Egyptians to put the interests of the nation above all else.
Egypt's ruling generals pledged last week to rebuild the torched church in Soul. The head of Al-Azhar, Egypt's most prominent Islamic institution, promised that Muslims would help in the reconstruction as a gesture of solidarity.
Sharaf also met Christians who have been protesting outside the TV building in Cairo to reassure them that his interim government would not discriminate against them.
In the meantime, the difficulty of keeping order continues.
Egypt's 500,000-strong security forces pulled out of Cairo and several other major cities three days into the uprising that began Jan. 25. They have yet to fully take back the streets.
Their still-unexplained withdrawal left space for a wave of violent crime and lawlessness in parts of the nation, especially in Cairo, a city of 18 million people that at the best of times looks chaotic.
Additionally, some 25,000 prisoners, including hardened criminals and drug barons, escaped from prisons during the uprising. Only 13,000 of them have been recaptured or surrendered voluntarily.
Attacks on police stations freed another 25,000 suspects, most of whom remain at large, according to security officials.
Only last week, inmates at prisons in two Nile delta towns _ Damanhour and Shibeen _ attempted jail breaks before guards regained control, killing three of them.
Over the weekend, crowds stormed at least six offices belonging to the hated State Security Agency, including its main headquarters in a Cairo suburb, clashing with officers inside and seizing documents.
The attacks followed reports on Facebook that State Security officers were destroying documents that could incriminate them if court cases were brought against them for human rights abuses. Dissolving the agency, blamed for the worst human rights abuses under Mubarak's 30-year rule, is a key demand of the youth groups behind the 18-day uprising.
The continuing security vacuum has prompted residents in some Cairo districts to form their own neighborhood protection groups to guard buildings. In some places, civilian volunteers are directing traffic after nightfall when traffic police disappear.
Cairo residents report robberies on highways, unheard of less than two months ago. Motorists driving against incoming traffic on one-way roads is not uncommon in Cairo now.
In a separate incident, at least two people were wounded when rival crowds threw rocks in Cairo's central Tahrir Square, the uprising's epicenter, according to an Associated Press Television News cameraman at the scene.
The violence pitted youths camped in the square to press their demand for a complete break with the ousted regime against another group opposed to their continued presence.
Later, army soldiers forcefully removed the protesters and their tents, scuffling with some and making several arrests.
U.S. State Department spokesman Mark Toner said Washington was concerned about the violence against the Coptic Christians and protesters. He said the U.S. had no indication that Egypt's military supported the attacks.
U.S. officials were talking to their Egyptian counterparts and urging them "to act swiftly and to bring the perpetrators of that violence to justice," he said..
"It's important for Egyptians to remember the sense of unity in Tahrir Square just a few weeks ago and to refrain from any kind of violence, and to go back to that sense of peaceful demonstration and expression," he said.
Associated Press writer Bradley Klapper in Washington contributed to this report.