In the first incident, seven middle school students got drowned when they were swimming in the Huihe river in Laiwu city of east China's Shandong province yesterday.
Their bodies were recovered later, an official said.
In another case, four students were drowned in Songhua river in Habrin, capital of northeast China's Heilongjiang province.
The incident happened when one female student slid to the river while she was washing her hands.
Five of her classmates, who tried to rescue her, also got submerged.
Two of them were saved by the villagers, while four got drowned.
Four fishing boats are working at the spot to retrieve the bodies, state-run news agency Xinhua reported.
