Obama canceled joint U.S.-Egypt military exercises scheduled for next month, although he gave no indication that the U.S. planned to cut off its $1.3 billion in annual military aid to the country. The U.S. administration has avoided declaring Morsi's ouster a coup, which would force it to suspend the military aid.
"While we want to sustain our relationship with Egypt, our traditional cooperation cannot continue as usual when civilians are being killed in the streets and rights are being rolled back," he said, speaking from his weeklong vacation in Massachusetts.
Obama said the United States informed Egypt's interim leaders Thursday morning about plans to cancel the military exercises. The president also ordered his national security team to "assess the actions taken by the interim government and further steps that we may take as necessary with respect to the U.S.-Egyptian relationship."
The Bright Star maneuvers, long a centerpiece of the deep ties between the U.S. and Egyptian militaries, were scheduled to have lasted about three weeks. Several other countries, including Turkey, Jordan and Britain, have also participated.
The U.S. and Egypt have not held the biennial exercises since 2009, as Egypt grappled with the fallout from the revolution that ousted its longtime autocratic leaders Hosni Mubarak. Morsi, a member of the Muslim Brotherhood, was elected president in 2012 during Egypt's first democratic elections.
Despite the curfew and state of emergency, violence spilled over to a second day Thursday.
The Interior Ministry said its decision to authorize police to use deadly force came after an angry crowd stormed the governor's office in Giza, the city next to Cairo that is home to the Pyramids.
Associated Press reporters witnessed the burning buildings in Giza — a two-story colonial-style villa and a four-story administrative building, located on the road that leads to the Pyramids on the west bank of the Nile River.
"The ministry has given instruction to all forces to use live ammunition to confront any assaults on institutions or the forces," the statement read.
Egypt's military-backed government also pledged in a statement to confront "terrorist actions and sabotage" allegedly carried out by Muslim Brotherhood members.
State TV blamed Morsi supporters for the arson and broadcast footage showing firefighters evacuating employees from the larger building.
The Brotherhood's website IkhwanOnLine said thousands of Morsi supporters marched through Giza but were attacked by pro-military "militias." It did not say how the government buildings were set on fire.
Attackers also set fire to churches and police stations across the country for a second day Thursday as several attempts by the Muslim Brotherhood devolved into violence.
The Brotherhood also called for protests on Friday, saying they would grow in intensity.
In the country's second largest city of Alexandria, Islamist protesters exchanged gunfire with an anti-Morsi rally, leaving scores injured, witnesses and security officials said. Attempts to storm police stations in the southern city of Assiut and northern Sinai city of el-Arish left at least six policemen dead and others injured.
Wednesday's violence started with riot police raiding and clearing out the two camps, sparking clashes there and elsewhere in the Egyptian capital and other cities.
Cairo, a city of some 18 million people, was uncharacteristically quiet Thursday, with only a fraction of its usually hectic traffic and many stores and government offices shuttered. Many people hunkered down at home for fear of more violence. Banks and the stock market were closed.
The turmoil is the latest chapter in a bitter standoff between Morsi's supporters and the interim leadership that took over the Arab world's most populous country. The military ousted Morsi after millions of Egyptians massed in the streets at the end of June to call for him to step down, accusing him of giving the Brotherhood undue influence and failing to implement vital reforms or bolster the ailing economy.
Morsi has been held at an undisclosed location since July 3. Other Brotherhood leaders, including several arrested Wednesday, have been charged with inciting violence or conspiring in the killing of protesters.
The Brotherhood has spent most of the 85 years since its creation as an outlawed group or enduring crackdowns by successive governments. The latest developments could provide authorities with the grounds to once again declare it an illegal group and consign it to the political wilderness.
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