Barack Obama seen nodding in quiet approval.

Via Foreign Policy:

In the early morning hours of Monday, the Egyptian military opened fire on pro-Mohamed Morsy demonstrators at the Republican Guard headquarters in Cairo, where the protesters had gathered to call for the release of the deposed president. At this point, the Egyptian Health Ministry is reporting that 42 people have been killed and over 300 injured.

It is unclear what precipitated the attack. While the overwhelming majority of those killed were pro-Morsy protesters, one army officer was also reported dead in the violence. Military officials are claiming that protesters attempted to storm the military building and kidnapped two soldiers. Morsy supporters, meanwhile, say the army opened fire on the sit-in during morning prayers.

Many of the injured were taken to a field hospital at the pro-Morsy demonstration near the Rabaa al-Adaweya mosque. The area is expected to be the site of pro-Morsy protests later in the day, and the Egyptian military has moved its forces close to the sit-in — raising the potential of further clashes later in the day. Meanwhile, the Muslim Brotherhood’s political party released a statement in response to the attack calling for an “intifada,” or uprising, against those who would “steal their revolt with tanks and massacres.”

The implications of this bloodshed are going to be severe — both in the political realm and on the street. Just as the attacks at Maspero or Port Said struck a blow against the post-Hosni Mubarak military government’s legitimacy, this attack threatens to seriously weaken the administration chosen to replace Morsy. President Adly Mansour, who is almost completely unknown to the Egyptian people, faces the first challenge of his administration.