Egypt's National Association for Change (NAC) has criticised comments by US ambassador to Cairo Anne Patterson regarding the Egyptian army and opposition protests on 30 June.
At a meeting with political parties and NGOs on Tuesday, Patterson said the US would not welcome the return of the army to power as an alternative to the Muslim Brotherhood.
The opposition will hold protests on 30 June calling for President Mohamed Morsi, who was propelled to power by the Muslim Brotherhood, to step down and call early presidential elections.
Patterson said the US was in direct contact with senior leaders in the Egyptian army.
The army does not want to retake power because it fears its relations with the Egyptian people would worsen, Patterson added.
Earlier this year, some anti-Brotherhood groups urged the army to retake power. Some even signed petitions to assert this demand.
NAC spokesperson Ahmed El-Noqr said in a statement on Wednesday that Patterson's statements were a "blatant interference" in Egypt's internal affairs.
He called on the foreign ministry to summon Patterson to "warn her against repeating them again [and] tell her she would be considered unwelcome in the country if she did."
The Egyptian army is a national institution "that belongs to the people and does not receive orders from abroad," El-Noqr added.
The Supreme Council of the Armed Forces (SCAF), comprising 21 senior military figures led by Field Marshal Mohamed Hussein Tantawi, ruled Egypt after the fall of President Hosni Mubarak in February 2011 until President Mohamed Morsi took office in June 2012.
The SCAF was criticised during its period of rule for failing to implement the demands of revolutionaries.
NAC is a pro-democracy umbrella group of liberal and Brotherhood activists formed in 2010 to coordinate opposition to Hosni Mubarak.
The meeting was held at the Ibn Khaldun Centre for Development Studies in Cairo.