Egypt's military chief, Gen. Abdul-Fattah el-Sisi, on Wednesday called on Egyptians to hold mass demonstrations to give the military a mandate to crack down on violence. The plea was seen as a direct threat to Islamists who have been staging protests demanding the return of Mohamed Morsi, the elected president and former Muslim Brotherhood leader the army removed from power three weeks ago.

"I'm asking you to show the world," Sisi said. "If violence is sought, or terrorism is sought, the military and the police are authorized to confront this."

Egyptians on all sides interpreted Sisi's words as a signal that he intends to intensify a crackdown on the Muslim Brotherhood and other Islamist groups, which dominated the government elected last year. In addition, Sisi's open animosity toward the pro-Morsi demonstrators has undermined his argument that the president's removal was a step toward restoring democracy, rather than a coup.

To Islamists, the message is clear. "Sisi's threats are a declaration of civil war," says the Muslim Brotherhood-led coalition that has been demanding Morsi's reinstatement.

If nothing else, it makes it difficult to take seriously Sisi's insistence that his goal is to unite all Egyptians. Here's Quentin Sommerville at BBC News on that point:

Gen. Sisi's call has been backed by Tamarod, the rebel movement that coordinated the protests in June which brought millions onto the street and resulted in President Morsi's removal. They say it's the army and the people against terrorism — but this is clearly the army and some of the people against the Muslim Brotherhood. [BBC News]

Sisi's remarks came hours after a blast in front of a Nile Delta police station killed one person and wounded 28 others. Nearly 170 people have died in Egypt's unrest since late June, and the rising tensions suggest more violence is to come. Indeed, the Muslim Brotherhood vowed to continue its protests despite Sisi's ominous words.

This power play could be a risky one for the army. The U.S., which sends Egypt's military more than $1 billion in aid annually, is obviously watching closely. The U.S. has stopped short of calling Morsi's removal a coup, which would force the U.S. to halt the aid by law. The Pentagon, however, just put a hold on the delivery of four F-16 fighter jets in a clear sign of disapproval over the way things have gone in the past few weeks.

The smart thing to do, some analysts say, is for the military to dial down the rhetoric instead of getting tougher. Peter Beaumont at The Guardian says that the military's heavy-handed approach — which includes keeping Morsi locked up somewhere — is only making Egypt more unstable.

While Morsi may have exacerbated Egypt's political crisis, claiming his victory at the ballot box as justification for his pursuit of a disastrous and increasingly unpopular agenda, holding him incommunicado only makes Egypt's crisis more fraught in the long run. Morsi represents a wide constituency. His detention, as Khalil al-Anani, a Middle East scholar at Durham University, argued forcefully earlier this month, far from persuading the wider Brotherhood to acquiesce, is likely to be counterproductive. [Guardian]