Islamist supporters of deposed Egyptian president Mohamed Morsi held demonstrations Friday, two days after the country’s constitution was suspended:

As helicopters circled and jets streaked over Cairo in a show of force from the nation’s powerful military, Islamist officials, who until earlier this week controlled Egypt’s government, launched a nationwide “day of resistance” against what they called a coup.

Although organizers called on supporters to remain peaceful, such rallies in the past have led to deadly clashes, and residents of Cairo and other areas were braced for chaos . . .

Tens of thousands sweltered in the midday sun outside the Rabia al-Adawiya mosque, listening as a speaker called Morsi’s ouster an assault on the dignity of the people of Egypt. “There are Americans and Zionists behind this,” the speaker said . . .

“We will have our legitimate president, or we will die as martyrs,” said Mohamed abu el-Makatem, an agronomist who traveled from Alexandria to the mosque in Cairo to attend the demonstrations. He said he did not expect an assault by the army but was worried about “thugs and police.”

Some of the men wept as they prayed. Many in the crowd waved the red, white and black Egyptian flag, just as thousands of anti-Morsi protesters had done on Wednesday, before the military forced the president from power. To the right of the podium, the black flag with white lettering used by the extremist group al-Qaeda and its affiliate Jabhat al Nusra, which is fighting alongside Syrian rebels against President Bashar al-Assad, was clearly visible . . .

Egypt’s generals moved quickly Thursday to put a civilian face on the takeover, installing the head of the Supreme Constitutional Court as interim president just hours after stepping in to force Morsi from power.

But the equally swift moves to arrest and charge leaders of 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 the past year.

William Booth and Abigail Hauslohner

Footage from Cairo appeared to show one demonstrator who had been killed. Visit this page for the latest news from Egypt.

Elsewhere in the Arab world, heads of state greeted Morsi’s ouster with enthusiasm:

The Islamist leader had failed to win allies abroad, much as he had at home, alienating Egypt’s traditional friends and foes alike with an often erratic foreign policy.

It also served as a reminder that most Middle Eastern leaders remain unelected, despite the upheavals since 2011 that have spawned new democracies in three of the Arab world’s 26 countries. In many of those nations where autocrats still rule, the Muslim Brotherhood poses the most potent challenge.

The region’s traditional Sunni Muslim monarchies made no attempt to hide their relief at Morsi’s ouster.

Saudi Arabia, which historically had close relations with Egypt but not with Morsi, hailed the “wisdom and moderation” of the Egyptian military for acting to remove him.

By doing so, the army “managed to save Egypt at this critical moment from a dark tunnel,” said a statement by King Abdullah.

Jordan lavished praise on the Egyptian people, saying that their “resolve has left the whole world amazed,” according to Foreign Minister Nasser Judeh. Young Egyptians in particular had brought “intellectual and moral credit to the Arab nation,” he said.

The United Arab Emirates, embroiled in a dispute with Morsi over its own crackdown against the Brotherhood, noted “with satisfaction” the developments in Egypt, a Foreign Ministry statement said.

Liz Sly and Ruth Eglash

Whatever government ultimately replaces Morsi will confront serious economic and political challenges:

Egypt’s economy is in tatters. Nearly a quarter of the work force is unemployed, and roughly half the population lives on less than $2 a day. The country owes billions of dollars in debt, its foreign currency reserves nearly exhausted. Prices are spiking, and shortages loom.

“Gasoline. Traffic. Bread,” said Ahmed Fadel Abuzeid, an electrician who camped in Tahrir to bring down Morsi. “We never had the power cuts before. And we never used to have these prices.”

There are no easy fixes. Many Egyptians turned against the Muslim Brotherhood-backed Morsi because of his poor stewardship of the economy, and experts say much of that blame was well-deserved. But Morsi also inherited the legacy of an authoritarian regime that over decades had rotted from within: a bloated bureaucracy, a costly and inefficient subsidy system and layer upon layer of corruption. . .

The economy won’t be the only problem confronting whoever next rules Egypt. The constitution that was ratified under Morsi has now been nullified, meaning this highly polarized nation must start from scratch in developing a set of common laws and principles.

After the military’s dramatic move on Wednesday, Egypt’s new leaders will need to restore a semblance of constitutional authority, said Tom Ginsburg, a professor of comparative and international law at the University of Chicago.

But to do that, “it must be accepted by a vast majority of the population,” he said.

That means getting the support of the Muslim Brotherhood and others who backed Morsi in elections just last year — a tall order at a time when many feel their democratic rights have been trampled.

Muslim Brotherhood officials who spoke at a news conference of Morsi supporters on Thursday said that participating in any process set up by the military is out of the question.

“Now you are talking about a dictatorship,” said Murad Ali, a spokesman for the group. “We are not accepting this.”

Abigail Hauslohner

For images from Egypt, see the gallery below.