The violence raging through the streets of Greece is not as clear cut as some would make it to be, there seems to be a convergence of agendas, with some protesting excessive use of force by the police, while others are taking advantage of the situation and rampaging for the right to invade a sovereign state.
Check out the video and see towards the end, all the Stop the War signs while someone happily shouts Allahu Akhbar. Not connected to Islam, huh Charles? KGS
Winds of Jihad has much more on it here.
UPDATE: Commenter Toby correctly points out that the BBC video is from an earlier demonstration. The point is though, Muslims are indeed involved in the rioting as well.