The United States is poised to suspend much of its military aid to Egypt due to Cairo's sweeping crackdown against supporters of ousted president Mohamed Morsi, US officials said Wednesday.

The decision would hold up the delivery of major weapons, including Apache helicopters, F-16 fighter jets and M1A1 Abrams tanks, officials told AFP, confirming overnight US media reports.

But American aid focused on counter-terrorism efforts -- including operations in the Sinai desert near Israel's border -- would likely continue, officials said.

An announcement of the move was expected within days but officials, who spoke on condition of anonymity, said Washington had already effectively frozen deliveries of expensive military hardware since a July 3 coup and subsequent bloody clampdown on the Muslim Brotherhood.

"Nothing's been delivered in months," one said.

After Morsi's overthrow, the Pentagon called off a planned exercise with Egypt and postponed the delivery of four F-16 fighters.

"I think it's fair to say that we will have a decision to announce once we've made the appropriate notifications," White House spokesman Jay Carney said.

But he said reports that Washington would cut off all aid to Egypt, which amounts to $1.5 billion a year, most of it in military hardware and training were false.

The review of US policy towards Egypt "is finished, and when we have something to announce we will," State Department deputy spokeswoman Marie Harf said Wednesday, also insisting that some form of US assistance would continue.

Washington will "keep working with the Egyptian government and Egyptian people to help them on this transition to democracy," she told reporters.

Obama and his deputies have repeatedly appealed to Egypt's military-backed government to hold fresh elections to restore democratic rule, but have so far failed to persuade Cairo to change its approach.

Harf said the US would "certainly... welcome and look for additional concrete steps for the interim government to move towards a transitional process."

In the latest bloodshed on Egyptian streets, Islamist backers of the ousted Egyptian president clashed with police on Sunday, leaving 57 people dead.

Asked last month if the United States would go ahead with a planned delivery of Apache attack helicopters, Defense Secretary Chuck Hagel said the administration was "reviewing all aspects of our relationship."

Israel, anxious about maintaining its 1979 peace accord with Egypt, has reportedly asked Washington to maintain aid to Cairo's military-led interim government.

The United States has provided billions in aid to Cairo since the 1979 peace deal, ensuring peace between Egypt and Israel as well as priority access to the Suez Canal and anti-terrorism cooperation.

"Picking up and leaving town and walking away from this relationship wouldn't be good for the Egyptian people," Harf added.

"It wouldn't allow us to help... move Egypt towards a more democratic place, and certainly in our shared security interests... that wouldn't help achieve those goals either."

Looking ahead, the United States has already deposited $584 million in remaining military aid funds for fiscal year 2013 in a federal reserve account pending the outcome of the policy review, according to State Department officials.