[quote]Two gunmen have been shot dead after they opened fire outside a conference on cartoons of the Prophet Muhammad in a suburb of Dallas, police say. A security guard was also injured. Police have put the Curtis Culwell Center in Garland on lockdown and told participants in the event not to leave. Dutch anti-Islamic politician Geert Wilders was attending the conference. Mr Wilders tweeted that shots had been fired and he had now safely left the building. It was not clear if the shootings were related to the event.[/quote]