China's top leaders have urged "all-out efforts" to treat those injured in a car attack in southern China, one of the deadliest incidents in the country's recent history, as online posts asking what the attack says about Chinese society were censored.

By Michael Zhang, with Matthew Walsh in Beijing Officials in southern China ramped up security on Wednesday at the site of one of the country’s deadliest mass-casualty events in years, snuffing out makeshift memorials to the 35 people killed when a man drove a car into a crowd at a sports complex.