Tens of thousands of supporters of ousted Thai premier Thaksin Shinawatra rallied against new leader Abhisit Vejjajiva Sunday, threatening to engulf the troubled kingdom in a fresh wave of unrest. The red-clad protesters massed a day before Abhisit was due to give his maiden policy speech to parliament, saying they would not give up until the government that came to power two weeks ago holds fresh elections. Most of the protesters gathered at a central Bangkok parade ground and organisers said they would move to parliament overnight. An advance guard of several hundred had already blocked a key road outside the legislature.