The US has urged Egypt’s leadership to stop the “arbitrary” arrests of Muslim Brotherhood members, warning against targeting any particular group.
“You’re working against yourself if your effort is to be inclusive,” White House spokesman Jay Carney said.
UN chief Ban Ki-moon also warned against the exclusion of any party.
Rival rallies are expected in Cairo on Friday amid rising tensions over the army’s overthrow of Islamist President Mohammed Morsi last week.
Supporters demanding Mr Morsi’s reinstatement have continued to stage mass protests in Cairo this week near the barracks – where he is believed to be being held.
On Thursday, the Obama administration and UN both raised concerns about Egypt’s decision to issue arrest warrants for the leader of the Muslim Brotherhood – to which Mr Morsi belongs – and nine senior figures of the movement.
“The only way this is going to work successfully… is if all parties are encouraged and allowed to participate and that’s why we’ve made clear that arbitrary arrests are not anything that we can support,” Mr Carney said.