Carrying sticks and makeshift sheilds, supporters of Egyptian president Mohammed Morsi appear to be prepared for anything as massive crowds stream into historic Tahir Square for demonstrations that call for the ouster of the president.
Egyptians and their security forces prepared for demonstrations on Sunday that may determine their future, two years after people power toppled a dictator and ushered in a democracy crippled by bitter divisions.
Mursi's Muslim Brotherhood can hope protests fizzle out like previous outbursts. If they do not, some form of compromise, possibly arbitrated by the army, may be on the cards.
Waving national flags, thousands gathered on Cairo's Tahrir Square, cradle of the 2011 uprising against Hosni Mubarak. They hope that, after the working day, millions will rally across the country to unseat President Mohamed Mursi - exactly a year since the Islamist became Egypt's first freely elected leader.
Across a capital eerily quiet for the start of the working week, Mursi supporters have also congregated - by a mosque not far from the suburban presidential palace. Liberal protest organizers plan to mount a sit-in outside from Sunday evening.
There was none of the street violence seen in the past week. Cairo's security chief said over 140 known troublemakers had been rounded up in the past day. Some were found with weapons.
Interviewed by a British newspaper, Mursi repeated his determination to ride out what he sees as an undemocratic attack on his electoral legitimacy. But he also offered to revise the new, Islamist-inspired constitution, saying clauses on religious authority, which fueled liberal resentment, were not his choice.
He made a similar offer last week, after the head of the army issued a strong call for politicians to compromise. But the opposition dismissed it was too little too late. They hope Mursi will resign in the face of large numbers on the streets. Some also seem to believe the army might force the president's hand.
An economic crisis, deepened by political paralysis, has encouraged some to take to the streets in protest. But many others fear renewed unrest will only make matters worse.
To acknowledge that the army has a role to play in the crisis is bad news for Morsi. There are still some Mubarak-era holdovers who wish to see him fail and the Muslim Brotherhood sent packing.
But realistically, the military will probably sit this one out unless things get out of control and the mob attacks government buildings and each other. That's the real threat. No one knows how far the Muslim Brotherhood is prepared to go in protecting Morsi but if things get unruly, they appear to be prepared to win the street battle despite being vastly outnumbered.
If the protests go on for several days, the patience of Morsi and the police will be tested. But past protests since Mubarak fell have petered out after a few days so we'll have to see how this one unfolds.