The Taliban has threatened to launch a fresh wave of violence at next month's presidential run-off in Afghanistan, and urged voters to boycott the poll. The warning came as campaigning opened.<br/><br/>In a statement emailed to news agencies the Taliban said the Islamic Emirate of Afghanistan once again urges their respected countrymen not to participate.<br/><br/>The Taliban called the elections an American process and said its fighters would launch operations against the enemy and stop people from taking part.