BEIJING—Back-to-back tornadoes killed 12 people in central and eastern China and left more than 300 others injured, authorities said Saturday. Eight people died in the inland city of Wuhan on Friday night and four others in the town of Shengze, about 400 kilometers (250 miles) east in Jiangsu province, local governments said. The first tornado struck Shengze about 7 p.m., damaging homes and factories and knocking out power, the state-run Xinhua News Agency reported. The Suzhou city government, which oversees the town, said in a social media post that four people had died and 149 others had minor injuries. Shengze is near Shanghai on China’s east coast. Another tornado hit Wuhan at about 8:40 p.m. with winds of 86 kilometers (53 miles) per hour, destroying more than two dozen homes and triggering a power outage affecting 26,600 households, Xinhua said. Officials in Wuhan said at a news conference Saturday that …