Cairo has battened itself down in anticipation of a massive backlash after this week’s massacre, one that produced a death toll that is now over 600 and still counting. The Muslim Brotherhood promises a “day of rage” after Friday prayer, and the military has blocked entry to Tahrir Square and other areas of the city. The Egyptian military has authorized the use of live ammunition against anyone attacking security forces as well, perhaps setting the stage for another massacre:

The government has authorized the use of deadly force against protesters targeting police and state institutions while the international community has urged both sides to show restraint and end the turmoil engulfing the nation.

Egyptian State TV reported Friday that army troops had been deployed to guard “vital installations” around the country, and CBS News correspondent Charlie D’Agata reported that the interim government seemed to be taken the Brotherhood’s threat of a day or rage very seriously.

While Cairo’s central Tahrir Square was deserted — and a heavy police presence was on-hand to try and keep it that way — thousands of Egyptians were expected to take to the streets after Friday prayers and vent their anger over the heavy-handed tactics used to quash the protests earlier this week. …

As turmoil spread, the Interior Ministry authorized the use of deadly force against protesters targeting police and state institutions. Egypt’s military-backed government also pledged to confront “terrorist actions and sabotage” allegedly carried out by Muslim Brotherhood members.

The Brotherhood, trying to regroup after the assault on its encampments and the arrest of many of its leaders, called for a mass rally Friday in a challenge to the government’s declaration of a month-long state of emergency and a dusk-to-dawn curfew.

Ha’aretz reports that the protesters have already taken to the streets by the thousands:

Thousands of Muslim Brotherhood supporters have taken to the streets in several Cairo neighborhoods and elsewhere in Egypt in defiance of the military-imposed state of emergency.

The protesters poured out of the mosques after Friday prayers, responding to the group’s call for a “Day of Rage” following the deaths of 638 people Wednesday when riot police backed by armored vehicles, snipers and bulldozers smashed the two sit-ins in Cairo where ousted President Mohammed Morsi’s supporters had been camped out for six weeks to demand his reinstatement.

Bloomberg wonders whether this is Egypt’s Tiananmen Square moment:

That means, in terms of deaths, we are now in the realm of China’s 1989 Tiananmen Square crackdown. The government’s official death toll there was 241, although few outside China believe that was accurate. U.S. intelligence at the time put it between 180 and 500; Amnesty International at up to 1,000; and others still higher. The Muslim Brotherhood is now estimating 2,000 died in Cairo. …

Admittedly, the Muslim Brotherhood protests aren’t the same as those by the students in Tiananmen Square. The Chinese protests were largely spontaneous, the protesters didn’t belong to any one organization, and they didn’t represent a (despotic albeit elected) previous government. Nevertheless, at least 700 people have died since the Egypt military assumed power in a coup July 3, most of them unarmed civilians. And it is just mendacious to suggest, as the Egyptian government does, that responsibility for the killing lies with the Brotherhood — no matter what the organization’s faults, and despite its members fighting back.

You have to ask: How would the world be reacting if the victims in Cairo were secularists or anti-communists?

Well, they’re not, and as Bloomberg notes, the indications from the first year of Muslim Brotherhood control wasn’t that the country was headed for a pluralistic, tolerant self-government.  In the wake of the massacre, the Brotherhood and its Islamist allies are torching Christian churches all over Egypt, part of a campaign against the Copts that had been simmering ever since Mohamed Morsi took power.  That doesn’t mean that the Egyptian military should be slaughtering them in the streets, or that they’re much better in practice than Morsi’s coalition was.  The lines are nowhere near as clear as they were in Tiananmen Square.

Of course, we also didn’t fund the Chinese military back in 1989, either.  Like it or not, this week has American fingerprints on it, and even with the murkier battle lines, that’s an embarrassment for the US.