Georgian police on Tuesday arrested a top opposition leader and used tear gas in a violent raid on his party headquarters, further deepening a political crisis sparked by last year's disputed parliamentary elections. Live television footage showed Nika Melia, the leader of the United National Movement, the country's main opposition party, being dragged from his party headquarters to be placed in pre-trial detention. Meanwhile hundreds of riot police used tear gas against his supporters and the leaders of all of the country's opposition parties, who have been camped out in the building since Wednesday, the Mtavari TV live pictures showed. im/reb