CAIRO — Ashraf Mohammed, 24, a flag vendor, woke up early Wednesday and took his wares to the front of the US embassy in downtown Cairo. He was selling black Islamist flags with the decree “There is no God but one God and Mohammed is his prophet” — flags that looked just like the ones used by Al-Qaeda.

Behind him, the walls of the American compound were overwhelmed with graffiti of crude curse words, as well as such phrases in Arabic like "Oh Obama, all of us are grandsons of Osama" and "Khaybar, Khaybar, oh Jews the army of Mohammed is coming." “United States of Muslim,” was scrawled on the front of the embassy. A white version of the Islamist flag hung limply from the center of the entryway as riot police stood idly underneath.

The night before, about 2,000 protesters marched to the US embassy in Cairo, reportedly wanting revenge for a little-known, badly-dubbed film in which the prophet Mohammed was depicted as having oral sex and promoting pedophilia, among other things. In fact, no one really knows who is behind the film, adding a surreal element to the saga.

In the sea of protesters outside the embassy — a mix of Salafis, Islamists and dissatisfied young men — there were an astonishing number of black Islamist flags being waved alongside Saudi and Egyptian colors. There was minimal security presence and some of the protesters breached the first wall of the compound, tore down the US flag and raised the black Islamist flag in its place.