Two days after Mohamed Morsi was deposed, Washington has still not termed his ouster "a coup," hoping warnings of cuts in US aid will prove enough leverage to force the Egyptian military to restore democracy.

The law is clear: under legislation dating back to 1985, US military and economic assistance to another country must be suspended if a legitimately elected government is overthrown by the army.

But the verbal acrobatics by the US administration to avoid the "c" word show President Barack Obama's desire not to undermine the generals amid the chaos of Morsi's ouster, hoping that, as they did in 2011 after the toppling of Hosni Mubarak, they will steer Egypt back toward democracy.

"None of the funds appropriated or otherwise made available... shall be expended to finance directly any assistance to the government of any country whose duly elected head of government is deposed by military coup d'etat or decree," states the law.

A special clause on Egypt also states the government must be supporting a transition to civilian government, but gives the secretary of state the right to grant a waiver and allow the aid anyway if it is in "US national security interests."

The US contributes military aid each year of some $1.3 billion -- out of a total aid package of about $1.5 billion -- covering about 80% of the cost of material and equipment for the Egyptian army. In practice, that has meant the US funds multi-year contracts with American manufacturers, particularly of tanks and fighter jets.

"It's not as though we give the Egyptians a check ... what they get is essentially their procurement material for the year, and it's valued at that amount of money," said Robert Satloff, director of the Washington Institute for Near East Policy.

"Now the administration can hold up deliveries of items if it chooses to do so, but the money itself has already been appropriated and much of it has already been expended."

A contract was signed for 20 F-16 fighters in 2010 with aeronautics giant Lockheed Martin, of which four were delivered in January, according to an independent congressional report. Since 1980, the Egyptian military forces have taken delivery of some 220 F-16s.

In the hours after Morsi was toppled, Obama said the US administration was "deeply concerned" by the turn of events, adding he had ordered a review of "the implications under US law for our assistance to the government of Egypt."

"The administration wants to see as quick as possible a return to civilian elected authority, and it's signaling that it has in its pocket the threat of suspending aid," Satloff explained to AFP.

Tamara Cofman Wittes, director of the Brookings Saban Center, told AFP the State Department would have to work through a "legal determination whether or not what happened in Cairo fits the definition of a coup established by Congress."

"So yes, that does provide time for the US government and the Egyptian government to have a set of conversations about what the military's intentions are, what the roadmap is, what the timeline is," she said.

"If they want to toss out last year's constitution and start over, that's going to take more time then if they just want to come up with some amendment to what they've got."

She recalled that, under direct military rule after Mubarak was ousted and before Morsi was elected, it was a "very fraught period," and there had been real concerns "about the way the military was governing Egypt and the rights abuses."

Democratic and Republican lawmakers have also avoided using the term "coup d'etat," waiting to see how things play out and what will be in the best interests of US national security.

Such interests include the Suez canal guarded over by Egyptian soldiers, recalled Michael Rubin, an expert with the conservative American Enterprise Institute think-tank, saying he did not "see a situation in which the Americans would antagonize the military to that extent."

"All of the ships from our East coast fleet which pass through the Mediterranean on the way to the Gulf go through the Suez canal," he told AFP.

But time could be on Washington's side, as US aid for the fiscal year 2014, set to start from October 1, is not due to be voted on by Congress until after its summer recess.