A group of US politicians have urged the White House to lift its suspension of military aid to Egypt, saying that freezing funds and weapons deliveries could unravel decades of co-operation with a key regional ally.

Democratic Representative Eliot Engel, the ranking member of the House foreign affairs committee, said on Tuesday he had initially supported a temporary halt to deliveries of F-16 aircraft to the Egyptian military following the removal of president Mohamed Morsi in July.

"But today I do not believe that suspending the military aid will make the Egyptian government more democratic or make it easier for the United States to influence its behavior in the future," he told the committee.

"In fact, I think it's more than likely to have the opposite effect. And I'm afraid it could jeopardize the close US-Egypt military co-operation that we've worked so hard to build over the last several decades."

The US earlier this month said it was recalibrating its $1.5 billion a year in annual aid to Cairo, including $1.3 billion for the military, after the bloody repression of Morsi supporters since his removal.

Marking a dramatic break with years of unqualified support to Cairo, President Barack Obama in early October decided to freeze large item orders, including Apache attack helicopters, F-16 fighter jets, M1A1 Abrams tank parts and Harpoon missiles.

'Made serious mistakes'

More than 1,000 people, mainly Morsi supporters, have been killed since July 3, and authorities have rounded up some 2,000 Islamists, including most of the Muslim Brotherhood's leadership.

Engel condemned the violence and agreed that "it's clear that the Egyptian military has made some serious mistakes in managing the ongoing transition."

"But if I were given the choice between the military and the Brotherhood, I'd take the military every time."

Committee chairman Ed Royce worried about harming security operations on the Sinai peninsula, and exposing other regional allies to greater insecurity.

Acting assistant secretary for the region, Beth Jones, told politicians that the US was continuing to supply spare parts so the Egyptian military could continue to operate its already formidable arsenal.

The administration's decisions would be reviewed, she assured, based on "credible progress on the interim government's political roadmap toward a sustainable, inclusive and peaceful transition to democracy."

Derek Challot, assistant defence secretary for international security affairs, hinted that while delivery of large systems could be resumed, the nature of US aid might change as it works with Egypt "to determine whether to sustain certain legacy systems that might otherwise be retired".