CAIRO (Update 2) - About six vehicles were set on fire outside the Interior Ministry in Cairo on Wednesday, and witnesses said the blazes were caused by disaffected police officers demanding their jobs back. Officials were not immediately available for comment. A security source earlier said a fire had erupted at a building used to store criminal evidence near to the Interior Ministry. Tanks and soldiers are still at intersections in Egypt's capital after Hosni Mubarak was toppled in an 18-day uprising during which the ruling headquarters was burned down in Cairo and police stations were set on fire throughout the country. Plain-clothed policemen and soldiers cordoned off the area around the ministry on Wednesday, pushing away hundreds of onlookers who came to see the burning vehicles. The ministry has been surrounded by army vehicles since the military deployed on Cairo streets on Jan. 28. Witnesses to Wednesday's incidents said the former officers poured petrol over the vehicles and set them alight. At least four fire trucks and four ambulances rushed to the scene. It was not clear if the perpetrators had escaped. "The ministry had told them they could have their jobs back, but when they went with their papers they were told to use the paper to drink water out of," said one witness, 30, who gave his name as Ashraf and had come to the ministry with his brother, a police officer who had lost his job.