More than 40 people are reported dead and hundreds wounded in Cairo on Monday following pre-dawn violence in which supporters of Mohammed Morsi and the Muslim Brotherhood were fired upon by Egyptian military and security personnel outside the military barracks where the ousted president is being held.

Witnesses at the scene describe differing accounts of what led to the shootings, but the violence is a troubling sign that tensions are likely to increase as the country seeks to negotiate its way out of a complex political crisis.

The military removed Morsi from power last week following the largest popular protests in Egypt's modern history. While many welcomed his ouster, including members of Egypt's pro-democracy left, the fear of deepening violence and instability has left many on edge as the country's military council has reasserted its authority.

Egypt's political crisis has deepened significantly now, warn observers, following what many—including opposition leader Mohammed ElBaradei—are calling a "massacre" by the army and security forces.

Following news of the bloodshed, ElBaradei tweeted:

Violence begets violence and should be strongly condemned. Independent Investigation a must. Peaceful transition is only way .

— Mohamed ElBaradei (@ElBaradei) July 8, 2013

Agence France-Presse reports that the National Salvation Front, headed by ElBaradei, issued a statement of its own in which it condemned the violence and demanded a full investigation into the incident.

Al-Jazeera reports:

The Egyptian health ministry said at least 42 people had been killed and more than 300 injured in the incident early on Monday morning.

Mohamed Mohamed Ibrahim El-Beltagy, a Brotherhood MP, described the incident during dawn prayers after police had stormed the site, as a "massacre".

About 500 people were also reportedly injured.

A doctor told Al Jazeera that "the majority of injured had gunshot wounds to the head".

Meanwhile, Egypt's military also shuttered the headquarters of the Muslim Brotherhood's Freedom and Justice Party in another move that political observers say reflects poorly on the hope that political reconciliation and inclusiveness will find a place in the transition period that is now taking place.

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