The Egyptian Actors Union has suspended the membership of prominent actors Amr Waked and Khaled Abul Naga over what the union called "high treason" after the two attended a Congress panel criticising proposed amendments to Egypt's constitution in Washington earlier this week.

The union said in a statement on Tuesday that the actors' actions are tantamount to "high treason", as the two actors unilaterally spoke to "external powers" to back the "agendas of conspirators" aiming to undermine Egypt's security and stability.

"The union announces the cancellation of their membership and distances itself from their actions," the union said in a statement, adding that it "would not accept any traitor to their homeland to be among its members.

Waked and Abul Naga, known for their pro-2011 revolution activism and their critical views of the government, attended on Monday a congressional briefing titled 'Constitutionalising Authoritarianism,' which tackled proposed amendments to Egypt's constitution that would allow President Abdel-Fattah El-Sisi to stay in office 12 more years after his second and last term ends in 2022.

The session was moderated by Congressman Tom Malinowski and attended by Human Rights Watch’s Washington director Sarah Margon; Bahey Eldin Hassan, director of the Cairo Institute for Human Rights Studies; and Dalia Fahmy, a professor of political science at Long Island University.

The proposed amendments, initiated by a pro-government parliamentary bloc, have ignited controversy. Those who back the changes say they are important for the stability of a country hit by years of political turmoil since the 2011 revolution, and are needed to allow the president more time to carry out his economic development plans. Opponents say the changes consolidate authoritarian rule.

The parliament is planning to hold a final vote on the amendments on 14 April before they are put to a national referendum.