Will the popular coup by the Egyptian army turn into a civil war on the Nile? Despite assurances earlier in the week by newly-installed president Adly Mansour that all political parties would participate in the new government, the army has begun to arrest leaders of the Muslim Brotherhood:

Egyptian authorities installed an interim president and ordered the arrests of senior leaders of the Muslim Brotherhood on Thursday, hours after the nation’s all-powerful military ousted Mohamed Morsi, the country’s first democratically elected leader.

The Egyptian armed forces were quick to put a civilian face on what their opponents have labeled a coup. But the swift moves against the military’s longtime nemesis, the Morsi-allied Brotherhood, suggest that the nation’s generals are in no mood to reconcile with an Islamist group that until Wednesday had effectively controlled Egypt’s highest office for a year. …

Egypt’s new president, a virtual unknown named Adly Mansour, vowed to include all sections of society, including Islamists, in an interim coalition government shortly after he was sworn in Thursday. But even as he spoke, an arrest warrant was issued for Mohammed Badie, the Muslim Brotherhood’s “supreme guide.”

An arrest warrant also was issued for Khairat al-Shater, a wealthy businessman who serves as Badie’s deputy and was widely seen as one of the real powers behind the Morsi presidency.

Morsi and his top aides were placed under house arrest at a military residence. At least three other Brotherhood officials were taken into custody.

The enmity between the Ikhwan and the army goes back decades.  Until Mubarak fell, the army controlled the government for decades and suppressed the Muslim Brotherhood and its Islamist agenda.  Morsi had an extraordinary opportunity over the past year to turn the tables on the military and make the Muslim Brotherhood ascendant while putting the military in a subordinate role to civilian authority.  Instead, thanks to the massive amount of incompetence and hubris generated by the Morsi regime, the Muslim Brotherhood made the military more popular than ever — and gave it an entirely new reason to suppress the Ikhwan.

The problem with that as a strategy is that it ends any sense of investment that the Muslim Brotherhood and their Islamist allies have in political engagement, as opposed to terrorism and armed insurrection.  And the result is rather predictable:

Islamist gunmen staged multiple attacks on security forces in Egypt’s troubled Sinai Peninsula early on Friday, two days after the army overthrew elected Islamist President Mohamed Morsi, security sources and state television reported.

The security sources said a soldier was killed and two were wounded when a police station in Rafah on the border with the Gaza Strip came under rocket fire. The police post is close to the local headquarters of military intelligence.

Earlier, attackers fired rocket-propelled grenades at army checkpoints guarding El-Arish airport, close to the border with the Gaza Strip and Israel, in the latest of a string of security incidents in the lawless region, the sources said.

A military helicopter fired a missile at one of the vehicles trying to attack the airport, Israel Radio reported. No casualties were reported as a result of the missile attack.

It was not clear whether the attacks were coordinated and in reaction to Morsi’s removal. Islamist militants believed to have links to al-Qaida have established a foothold in the sparsely populated desert peninsula, sometimes in league with local Beduin smugglers and with Palestinian terrorists from Gaza.

It’s not as if this just started with Morsi’s downfall.  Radical Islamists had been attacking tourist centers in the Sinai for months, and the damage to the tourism industry (along with Islamist attacks on Christian churches throughout Egypt under Morsi’s rule) created a big economic disaster for Egypt and produced a widespread hunger problem, both of which were the proximate causes of the popular coup that took place this week.  Now, however, the attacks are no longer a headache for Morsi but for the military, and now the Islamists have no reason to hold back.

Earlier today, the African Union weighed in on the overthrow of Morsi with a finger wag to the military:

The African Union announced Friday that it has suspended Egypt.

The AU’s Peace and Security Council also said it was sending a team of “high-level personalities” to Egypt to work toward restoring constitutional order.

The moves, announced in separate tweets, come two days after the military overthrew the nation’s first democratically elected president and on the same day that massive demonstrations — some in favor and others in opposition to the coup — were planned.

I doubt that Mansour and military chief al-Sissi are terribly concerned with their standing in the African Union at this point, although they might be amused by their sudden taste for non-elected government, considering the current membership of the AU.

Update: Several pro-Morsi demonstrators have been wounded by gunfire while marching toward a military barracks where Morsi is being held.

A witness told Reuters that he saw several people fall to the ground, wounded by shotgun pellets. Security forces were cordoning the Republican Guard barracks but it was not immediately clear who had opened fire.

The BBC reports that at least one has died in the gunfire:

Shooting has broken out at a gathering of supporters of ousted Egyptian President Mohammed Morsi in Cairo, with at least one death.

The incident occurred as crowds tried to march on the place where Mr Morsi is believed to be held.

Morsi supporters have called this a Day of Rage, and it may get worse before it’s over.