President Barack Obama has ordered a review of US assistance to Egypt's government, the Pentagon said in a statement on Wednesday.

"Given the events of last week, the President has directed relevant departments and agencies to review our assistance to the government of Egypt," the Pentagon statement said, without explicitly referring to last week's military-backed overthrow of Egypt's president.

While US law requires aid to be cut off if a country's military ousts a democratically elected leader, the US diplomats said the move is unlikely.

Egypt receives annual assistance of $1.5 billion from Washington, most of which goes to the Egyptian military.

The White House said on Wednesday that it would take time to determine whether to call the removal of President Mohamed Morsi in response mass street pressure last week a military coup.

The White House has said it is not in the best interests of the United States to immediately change its aid programme to Egypt.