The premier also decried the recent suicides by monks and nuns in Tibetan-dominated areas, seeking the return of spiritual leader the Dalai Lama, as "radical" moves.
Answering questions for the first time on the situation in Tibet and the four neighbouring provinces, following over 25 self-immolation attempts, Wen said at his annual press conference today that China is opposed to such radical measures.
"The so-called Tibetan government in exile in Dharmashala in India is by nature a theocratic one, both under the direct control of the Dalai Lama or under his indirect influence," he said in his last annual press conference before his expected retirement later this year.
"The purpose of it is to separate Tibet and the Tibetan inhabited areas, the four provinces from China. We have a firm position and principle on this matter," he said.
"At the same time I should point out that all should recognise that Tibet and Tibetan inhabited areas of four provinces are inseparable part of China's territory," he said.
Referring to the recent spate of suicides and attempted self immolations, he said such behaviour was distressing.
"We are opposed to taking such radical moves which disturb and undermine social harmony. The young Tibetans are innocent. We are deeply distressed by their behaviour," he said.
Chinese officials have blamed the Dalai Lama for instigating the suicides though Wen did not directly blame the Tibetan spiritual leader.
At the same time, Wen admitted that development in Tibetan areas had lagged behind compared to mainland China.