Chinese Premier Wen Jiabao (front L) speaks as he inspects the drainage of the Tangjiashan quake lake in southwest China's Sichuan Province on June 5, 2008.

Chinese Premier Wen Jiabao went to oversee the safety of the Tangjiashan quake-formed lake by helicopter on Thursday afternoon.

"Now it's a critical moment for the Tangjiashan quake lake, and the most important thing is to ensure there is no casualty of the people," Wen said.