Six children, aged from five to 11, drowned while skating on a frozen river in Pingyao county, Shanxi province, on Saturday afternoon. The children fell into the water as they skated on the thin icy surface of the Nanzheng village section of the Huiji River, a tributary of the Fen River, the county government said. County police received the accident report before 5pm. An hour later, four of the children were found. The remaining two were found at around 7.30pm. They were taken to two hospitals, but none survived. An official in charge of county publicity told the South China Morning Post that five of the children were cousins and one was a neighbour's child. Critics have slammed the county government's inefficiency in bringing help to the children, but the official said all rescue work had to first guarantee rescuers' safety. Saturday's tragedy was the latest in a spate of drownings of children. On January 17, a girl and her two brothers drowned in Maoming , Guangdong, after falling into water while picking wormwood leaves. Two days later, four children - the oldest aged 13 - from Huilai drowned while playing in a fishing pond. On January 21, another four children from Huozhou , Shanxi, fell into the frozen Fen River while playing on the ice. The string of recent drownings prompted the Ministry of Education to issue a circular last month, urging parents to supervise their children's safety and teach them not to play near waterways without barriers or on frozen rivers. A guideline issued by the National Health and Family Planning Commission three years ago said drowning was the leading cause of death on the mainland among children under 14.