US president Barack Obama has stopped short of calling the military's overthrow of democratically elected president Mohamed Morsi a coup d'état.

If the US declares Morsi's ousting a coup, the government would be forced to suspend all aid to the country - $1.5bn. The aid to its long-time ally constitutes America's principal leverage over the Arab world's most populous nation.

US law bans "any assistance to the government of any country whose duly elected head of government is deposed by military coup d'état or decree".

Obama said he was deeply concerned by the army's actions but did not mention the word "coup" and did not advocate Morsi's return.

"I 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 through an inclusive and transparent process, and to avoid any arbitrary arrests of President Morsi and his supporters," Obama said.

Millions of Egyptians rallied in favour of Morsi's departure during demonstrations that eclipsed even the protests that brought down Hosni Mubarak. The military suspended the constitution but installed a new interim government presided over by Adli Mansour, top judge of Egypt's constitutional court. It also gave a clear roadmap for return of civilian rule that was welcomed by Egypt's religious and political leaders.

British foreign secretary William Hague said the UK did not back military intervention and urged for a calm transition. "The situation is clearly dangerous and we call on all sides to show restraint and avoid violence," he said.

"The United Kingdom does not support military intervention as a way to resolve disputes in a democratic system."

"The chance of a democratic future was hard won for Egypt by the Egyptian people two and a half years ago. But looking forward, we call on all parties to show the leadership and vision needed to restore and renew Egypt's democratic transition," he said.

"It is vital for them to respond to the strong desire of the Egyptian people for faster economic and political progress for their country.

"In our view this must involve a political process that includes all groups on an equal footing leading to early and fair elections which all parties are able to contest, and civilian-led government... In the long run only democratic processes and government by consent will bring the stability and prosperity that the people of Egypt seek."

Egyptian military have guaranteed the Obama administration they are not interested in taking power in the long-term.

However, press freedom organisations have expressed their concerns for a military raid on Al-Jazeera's Egyptian station and the shutdown of other three pro-Morsi broadcast.