At least 40 people were reportedly killed as security forces started an operation to clear pro-Morsi protesters who have been camped out on the streets of Cairo since the Egyptian president was deposed by the military last month. On Wednesday morning, live footage from Cairo showed smoke engulfing Nahda square - which was later completely cleared - and there were reports of tear gas and birdshot being used on supporters of the ex-president Mohamed Morsi, who was removed from power on July 3. Al Jazeera's Dominic Kane reports.