President Barack Obama on Wednesday called for a swift return to elected civilian rule in Egypt, saying the United States was "deeply concerned" by the military's toppling of Mohamed Morsi.
Obama also sent a signal to military leaders, ordering a review of the hundreds of millions of dollars in annual US aid to Egypt in light of the army's move against Morsi, the nation's first democratically elected president.
"I now call on the Egyptian military to move quickly and responsibly to return full authority back to a democratically elected civilian government as soon as possible," Obama said, just hours after Morsi's ouster.
In Obama's strongest statement to date on the mounting crisis in Egypt, he also urged the powerful army to refrain from any arbitrary arrests and to protect the rights of all Egyptians.
But his statement fell short of condemning the military action, in what a US official told AFP on condition of anonymity was a bid to strike a balanced tone and "avoid a spiral into violence."
Washington finds itself walking a tightrope, caught between the need to defend a democratically elected president while recognizing that Morsi failed during his year-long rule to meet the aspirations of many Egyptians who fought to oust long-time autocrat Hosni Mubarak.
Analysts and lawmakers have for months sharply criticized the tepid US response to Morsi's failure to usher in a more inclusive government and instigate badly-needed economic reforms.
"In what has to be one of the most stunning diplomatic failures in recent memory, the United States is -- in both perception and reality -- entrenched as the partner of a repressive, Islamist regime and the enemy of the secular, pro-democracy opposition," wrote Republican senator Ted Cruz in Foreign Policy magazine on Wednesday.
During days of recent unrest, US officials struggled to articulate a strong response, saying democracy takes time to build and that it was not taking sides in the power struggle.
Obama highlighted the administration's dilemma, saying "the voices of all those who have protested peacefully must be heard -- including those who welcomed today's developments, and those who have supported President Morsi."
As emergency talks were held at the White House, the State Department ordered most of its staff to evacuate the Cairo embassy, which in the past has often been the focus of anti-US protests.
From the beginning of Morsi's rule in June 2012, Washington has sought to cajole him into meeting the huge expectations that his election would mark the dawning of a more democratic era.
The US official assured AFP that longer term Washington was seeking to lay out a process to help Egypt get back to a democratic process, while retaining "flexibility" for US actions as the events unfold.
The ousting of Morsi could have wider implications for the $1.3 billion in annual US military aid to Egypt. Under US law, Washington may have to suspend that aid as well as millions more in economic assistance.
Obama said he had "directed the relevant departments and agencies to review the implications under US law for our assistance to the Government of Egypt."
This could give the US some leverage going forward, acting as an incentive for the military to stick to armed forces chief General Abdel Fattah al-Sisi's vow to "remain far away from politics."
While what happened in Egypt "may technically be a coup d'etat" it should not necessarily be seen as an "interruption of Egypt's democratic development," argued Brian Dooley, from Human Rights First.
"The Morsi government has been a great disappointment to the people of Egypt," agreed Senator Patrick Leahy, the head of a budgetary committee on foreign operations.
He warned the law was clear and that "US aid is cut off when a democratically elected government is deposed by military coup or decree."
Many Egyptians have welcomed the military intervention and believe the army -- largely trained and equipped by the United States -- will work to preserve the country's new-found democracy.
In April, US Secretary of State John Kerry praised the army for its restraint and role in the 2011 uprising.
"I think the military has been the best investment that America has made in years in that region," Kerry told US lawmakers .
"The army in Egypt has been, frankly, an incredibly responsible player in this drama. But for the army, you would have had a civil war... You would have had massive bloodshed."