CAIRO – 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 the Egypt’s ousted president, security teams led by the Muslim Brotherhood were busy early Monday filling sandbags and erecting brick walls.

They were fortifying themselves for what the backers of toppled president Mohammed 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 around Cairo University and Rabaa al-Adawiya mosque for more than a month.

Two weeks ago, the cabinet of the military-backed interim government signaled it had given the go-ahead to Interior Ministry forces 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 celebration of Eid over, men gathered around TV screens at the mosque encampment and listened Sunday night to reports on 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 it 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.

The military and police have twice fired into crowds of pro-Morsi demonstrators, saying they were provoked by armed protesters.

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