Dozens of tanks and armored personnel carriers fanned out across the city of 18 million, guarding key government building a day after large, violent confrontations emboldened the movement demanding a change of leadership. There was rampant looting across the sprawling city of 18 million and a growing feeling of fear and insecurity.RELATED:Editorial: A region in ferment'Police open fire as protesters re-gather in Cairo'Mubarak sacks gov't; defends police crackdown on protestersIn the city's main Tahrir Square, at the center of Saturday's massive demonstration, there was only a light military presence — a few tanks — and soldiers are not intervening. Few police were seen in the crowds and the protest began peacefully but then police opened fire on some people in the crowd near the Interior Ministry and a number of them were wounded by gunshots. It was not clear whether they used rubber bullets or live ammunition.