The cause of the blast was not immediately clear but onesecurity official said it was a car bomb. There was no immediateclaim of responsibility.MENA cited a senior security source as saying preliminaryinvestigations indicated that attackers had placed a bombunderneath a car near the consulate and remotely detonated it.MENA earlier cited a security source as saying two policemenwere wounded in the attack. Militants have carried out roadside bombs and suicide bombing attacks which have so far targeted members of the security forces and officials.The violence, and political turmoil triggered by the 2011 uprising that toppled autocrat Hosni Mubarak, have hurt Egypt'stourism industry, a pillar of the economy. Media reports said an Egyptian was wounded by the blast.The blast occurred early in the morning on a weekend during theMuslim holy fasting month of Ramazan - a time of day when thereis little congestion.The MENA report cited witnesses as saying the explosion hadcaused massive destruction to the building. The force of the blast shook a building in downtown Cairo and could be heard inmany neighbourhoods.A Western diplomat said he was aware of the explosion in front of the consulate but could not confirm that the building was the target. A Sinai-based insurgency has escalated since the army ousted President Mohamed Mursi after mass protests against his rule in 2013.Two weeks ago, a car bomb killed the country's top public prosecutor and militants affiliated to Islamic State attacked several military checkpoints in North Sinai, in what was the fiercest fighting in the region in years.The army said 17 soldiers and more than 100 militants were killed in those clashes.