At least 74 people were injured after a massive fire engulfed a hotel and several nearby buildings in a busy commercial area in downtown Cairo early Monday, according to Egypt's ambulance services.No deaths were reported and most of the injured had breathing difficulties, the Ambulance Authority said. Half of the people were treated at the site and the rest were taken to nearby hospitals.The cause of the blaze was not immediately known and an investigation was under way.The fire started shortly after midnight inside the six-story Hotel Andalusia in the populous and dilapidated Ataba neighbourhood. The flames quickly spread to at least three adjacent buildings, including a warehouse, according to an Interior Ministry statement.