A man has been killed and dozens of police injured in clashes between Indian police and protesters in Darjeeling, an official said Sunday, as unrest worsens in the hill resort at the height of the tourist season.

Nearly 50 people, mostly police, have been injured in riots and arson attacks that have gripped the usually bustling area for more than a week and caused thousands of mostly Indian tourists to pack their bags and flee.

As the violence escalated sharply on Saturday, a man died in clashes as protesters torched cars and set upon police with knives, who responded with tear gas and baton charges.

"A man was killed and at least 35 policemen were injured yesterday. Some of them were stabbed in the back," the director general of West Bengal state police, Anuj Sharma, told AFP.

One officer who intervened in an arson attack was "seriously wounded after protesters slashed his throat", Sharma said.

The dead man appeared to have been shot but the circumstances were still unclear, Sharma added. Police have denied using live ammunition.

The upswing in violence began when police raided the homes and offices of members of the Gorkha Janmukti Morcha (GJM), a separatist movement that has long called for a new state of "Gorkhaland" to be carved out of West Bengal.

The group has accused police of shooting dead three of its members in Saturday's clashes -- a claim which police have strongly denied.

"Three of our comrades were killed and five were critically injured in police firing yesterday," GJM's general secretary Roshan Giri told AFP.

He said hundreds took to the streets of Darjeeling on Sunday for a silent protest against "police atrocities", waving India's tricolour flag and posters calling for peace.

The hills are famous for the Darjeeling tea whose production is jealously guarded. It is also famed for its "toy train" -- a 78-kilometre uphill ride from New Jalpaiguri.

But the troubles have dealt a major blow to the crucial tourism industry, leaving the normally busy destination deserted as shops, schools and banks closed.

Apart from the campaign for a new state, tensions have risen recently over a decision to introduce the Bengali language in schools, angering the Nepali-speaking Gorkhas.