Protesters in Egypt have climbed the walls of the American embassy in Cairo, and torn down a stars and stripes, tearing it to pieces and setting it alight.

It appears the protesters were angry at an unspecified film, or an event in which the fundamentalist Christian pastor Terry Jones was taking part in Florida called “International Judge Mohammed day”. This was a mock trial of the prophet, broadcast on the internet. Last year Jones angered Muslims worldwide by burning a copy of the Koran.

Some called on Egypt’s President Morsi to take action. Many in the crowd were supporters of Islamist groups.

Or the protest may have been about a film produced by Jones that insults Mohammed, according to the protesters, and was financed by Egyptian Coptic Christians living in the USA. No-one is entirely sure.

The police stood by to let the crowd spend its anger, then broke up the rally peacefully.