Four people have been seriously injured after a school bus rolled south of Mafeking on Tuesday morning.Swan River RCMP said the accident happened about 8:35 a.m., after the school bus, carrying a number of children, rolled over while travelling on Hwy. 10, about 13 km south of Mafeking. "Four patients suffered significant but non-life-threatening injuries and are being transported to hospital," said RCMP in a release."Multiple other children were being treated for injuries at the scene as well as taken to hospital."RCMP will update the situation when more information is known.Mafeking is 550 km northwest of Winnipeg.