Past the bouncy castle and the inflatable kiddie pool, past the potted plants, cashew vendors and signs welcoming visitors to come in peace to the protest rally and sit-in by supporters of Egypt’s ousted president, security teams led by the Muslim Brotherhood were busy early Monday filling sandbags and erecting brick walls reinforced with rebar.

They were fortifying themselves for what the backers of toppled president Mohamed Morsi say could be a bloody siege of two massive encampments in Cairo, both still filled with women and children.

Egyptian security officials warned media Sunday that time was running out for the tens of thousands of pro-Morsi demonstrators who have been camped out near Cairo University and the Rabaa al-Adawiya mosque for more than a month.

Two weeks ago, the cabinet of the military-backed interim government signaled it had given Interior Ministry forces the go-ahead to use “all necessary measures” to break up the two sprawling sit-in sites.

More than 130 of Morsi’s supporters were killed in two deadly incidents when they confronted security forces. Many were shot by military snipers or plainclothes police.

With the Ramadan month of fasting behind them and the celebration of Eid over, men gathered around TV screens at the mosque encampment and listened Sunday night to reports on the pan-Arabic news channel al-Jazeera stating that security forces would begin to cordon off the sit-in on Monday morning, issue ultimatums to clear the area, and then stop the flow of food and water.

There has been, however, no official statement by the government that police will shut down the protest.

But inside the encampments, Morsi supporters believed such a move was imminent.

Organizers at the sit-in declared their own “state of emergency” on Saturday, issuing a call for doctors and nurses to come to the site to help with casualties.

“We are ready for whatever comes,” said Mohammed Ads, a medical resident who manned a makeshift emergency clinic filled with donated drugs and medical supplies.

As the young doctor spoke, a woman lay sprawled on a mattress behind him, attached to an intravenous bag.

“What do we have to fear?” the doctor said. One of his paramedics interrupted to say, “We will either die or not die, so there is nothing to be afraid of. Our friends have died, and so we can die, too.”

The protesters said they expected to face water cannons, tear gas and then bullets.

The military and police have twice fired into crowds of pro-Morsi demonstrators, saying they were provoked by armed protesters who hurled molotov cocktails, rocks and bottles at them.

Inside the encampment, vendors sold gas masks, and in many crude wood and tarp shanties, residents kept bottles of vinegar for stinging eyes.

“Since the people have heard the military is coming soon to disperse us, more and more have come,” said Ibrahim Hussein, 28, who teaches computer classes.

“We are protesting for God, and so God will protect us,” he said. Hussein wore an orange vest and a helmet and carried a wooden baton because he was on security detail. Behind him were rows of sandbags piled chest high.

“Our morale is very high,” said Ibrahim El-Hawari, 49, a retired military officer. “We will not run.”

The men spoke easily of offering themselves up to martyrdom. Perhaps it was bravado, and maybe if the tear gas cans start to fly, they will disperse.

Nearby was a tent operated by Youth Against the Coup, lit with the glare of florescent bulbs. Its walls were covered with photographs, macabre head shots of the distorted faces of dead men and boys who were shot, they said, by the Egyptian security forces over the past month.

Many Egyptians say they are tired of the pro-Morsi encampments. Liberal and leftist political activists, who rallied the people to oust Morsi with the help of the military, have called for the camps to be shut down.

The nation’s top military commander, Gen. Abdel Fatah al-Sissi said that a mass rally he called for two weeks ago to demonstrate support for Egyptian security forces shows that the people support a tough stance against pro-Morsi protesters.

On early Monday, though, mothers with strollers were winding their way through the sit-in outside the mosque, and children with toy guns were running around, pretending to shoot one another.