Egyptian human rights organizations strongly condemned "the excessive force used by army and security forces against supporters of deposed President Mohamed Mursi" in a statement issued Tuesday.

The statement was issued in response to the violence that took place in the early hours of Monday outside Cairo's Republican Guard headquarters, which left at least 55 dead and over 400 injured, according to health ministry officials.

The non-governmental organizations (NGOs) said in their statement that responses to demonstrations must comply with international standards, even if demonstrations witness violence or the use of firearms.

"International standards do not allow the excessive use of lethal force, nor do they justify the intentional murder of large numbers of protestors by snipers belonging to police or military forces."

The statement added, "The use of force must not exceed what is required to prevent the use of violence by armed individuals."
 
At the same time, the NGOs also strongly condemned "the ongoing incitement to violence and killing by the Muslim Brotherhood and its supporters as well as their incitement to participate in widespread clashes."

The statement explained that such incitement only serves to "further deepen the political crisis in Egypt."

"We condemn all forms of violence committed by some segments of Islamist groups, including the violence committed in the Manial and Maspero areas of Cairo and in the Sidi Gaber area in Alexandria."

The undersigned organizations also denounced what it described as violations which have targeted the Muslim Brotherhood and its supporters in Sidi Beshr, El Zagazig, and elsewhere, as well as the incitement against them by some media outlets.

In their statement, the NGOs stressed that a fair, independent investigation "into this massacre will require the participation of independent human rights organizations and the immediate release of the findings to the public."

They demanded that the investigating committee be comprised of judicial and rights figures known for their professionalism and impartiality.

The statement was signed by 15 NGOs, including Cairo Institute for Human Rights Studies, Andalus Institute for Tolerance & Anti-violence Studies, Arab Penal Reform Organization, Arabic Network for Human Rights Information, Association for Freedom of Thought and Expression, Egyptian Center for Economic and Social Rights, Egyptian Initiative for Personal Rights and Hisham Mubarak Law Center among other organizations.