BEIJING—Chinese Premier Wen Jiabao says riots in Tibet caused heavy loss of life and that the government acted with extreme restraint in putting down the protests.

Wen’s comments Tuesday were the highest-level response to the violence in Tibet, rocked by the biggest anti-government protests in nearly two decades.

Wen also said that supporters of the Dalai Lama were behind the protests.

The unrest in Tibet began March 10 on the anniversary of a failed 1959 uprising against Chinese rule in the region that sent the Dalai Lama and much of the leading Buddhist clergy into exile.

“The Chinese government will unwaveringly protect its national sovereignty and territorial integrity,” ministry spokesman Liu Jianchao said at a hastily called news conference Monday night. “The violent acts have demonstrated the true nature of the Dalai clique.”