Lobsang Sangay, a 43-year-old Harvard scholar, took office Monday as head of the Tibetan government in exile, vowing to free his homeland from Chinese "colonialism".

After being sworn in at a colourful ceremony in the Indian hill town of Dharamshala, Sangay warned China that the Tibet movement was "here to stay" and would only grow stronger in the waning years of the Dalai Lama.

In an historic shift from the dominance of Tibetan politics by religious figures, the new prime minister, who has never set foot in Tibet, is assuming the political leadership role relinquished by the 76-year-old Dalai Lama in May.

In his inauguration speech, Sangay sought to dismiss concerns that the Dalai Lama's advancing years and eventual death would mark the demise of the movement that the Nobel peace laureate has led since fleeing his homeland in 1959.

Sangay said his election in April had sent "a clear message to the hardliners in the Chinese government that Tibetan leadership is far from fizzling out."

He pledged to sustain the movement "until freedom is restored to Tibet," stressing that the fight was "not against the Chinese people or China as a country.

"Our struggle is against the hardline policies of the Chinese regime in Tibet... against those who would deny freedom, justice, dignity and the very identity of the Tibetan people," he said.

"There is no 'socialism' in Tibet. There is colonialism. Chinese rule in Tibet is clearly unjust and untenable."

Sangay's age and former membership of the pro-independence Tibetan Youth Congress has fuelled speculation that he may harbour a radical agenda of seeking full independence for Tibet.

In his speech, however, he stressed his commitment to the principle of non-violence and support for the Dalai Lama's "middle-way" policy, which seeks "meaningful autonomy" for Tibet under Chinese rule.

Despite devolving some powers to a democratically-elected premier, the Dalai Lama will retain the more significant role of Tibet's spiritual leader and a major influence on major policy-making decisions.

The political transition makes Sangay a far more prominent figure than his predecessor as prime minister, but the challenges he faces are daunting.

The government-in-exile is not recognised by any foreign states, China refuses to acknowledge it, and its legitimacy in the eyes of Tibetans in Tibet might be questioned without the Dalai Lama's patronage.

Born and raised in the northeast Indian tea-growing region around Darjeeling, Sangay went on to study at Delhi University before completing a master's degree at Harvard Law School.

He took up residency in United States and became a senior fellow at the school.

His profile is not unusual among the new generation of exiled Tibetan activists who, while observant Buddhists, see their professional qualifications as a crucial asset for leadership.

Before his election, he was little known outside the narrow confines of the exile community.

Monday's ceremony, presided over by the Dalai Lama, was held in the Tsuglagkhang Temple, the spiritual centre of Dharamshala where the government in exile is based.

The Dalai Lama fled Tibet following a failed uprising against Chinese rule in 1959. He later founded the government in exile in Dharamshala after being offered exile by India.

Following traditional offerings of tea and sweetened rice, Sangay took the oath of office at exactly nine seconds after 9:09am (0339 GMT) -- the number nine being auspicious.

At a press conference afterwards, Sangay acknowledged that he was unlikely to be involved in direct talks with Beijing, which refuses to negotiate with anyone except envoys of the Dalai Lama.

"If China doesn't want to talk to me as a person and only with the representatives of His Holiness, it's fine with us," he told reporters.

"What we are interested in is resolving the issue. It's not about personalities."