By Subir Bhaumik
BBC News, Calcutta
Many tourists are trying to leave the area. Photos: Sanjay Sah
At least 15 people have been wounded in clashes between Nepali-speaking Gorkhas and Bengali and Hindi-speakers in India's tea-producing Darjeeling area.
The clashes occurred during an indefinite strike called by a Gorkha political party. The protest has paralysed life in the region.
Tens of thousands of tourists visiting Darjeeling are also stranded.
On Monday, the Gorkhas protested saying their supporters had been attacked by workers of the state's ruling Marxists.
The communists have denied the charge.
Darjeeling - in the north of the eastern state of West Bengal - is home to hundreds of tea gardens and produces Darjeeling tea which is coveted for its flavour.
The Gorkhas fought for a separate state through the 1980s but later settled for regional autonomy.
The recently-formed Gorkha Janamukti Morcha (GJM) has revived the struggle for a separate state.
All three areas in the region - Darjeeling, Kalimpong and Kurseong - are affected by the strike call.
Police intervened and used baton charges to break up clashes in Birpara, Hamiltongunje, Kalchini and Odlabari - small urban settlements.
"The situation is very tense throughout the Darjeeling region and its foothills," said district magistrate Rajesh Pandey.
The strike call has left tens of thousands of tourists stranded in the area.
"We have asked all tourists to leave immediately," said GJM secretary Roshan Giri.
The strike has shut down the hill town
"We are forced to call this indefinite strike because we have lost all faith in the West Bengal government," he said.
"They are stopping us from holding rallies peacefully, they are trying to provoke an ugly situation. So we will continue this strike until we achieve a separate state for Gorkhas," he said.
On Monday, the GJM held a strike in the region to protest against Sunday's attack on their supporters allegedly by the workers of West Bengal's ruling Marxists.
The GJM supporters were blocking a national highway leading to Darjeeling when they came under attack, Mr Giri said.
"The attack was unprovoked," he added.
The foothills are dominated by Bengali and Hindi speakers, while the Darjeeling hills are dominated by Nepali-speaking Gorkhas.
The Marxists denied they had any part in the attack.
The Gorkhas fought for a separate state under the leadership of the Gorkha National Liberation Front (GNLF) in the 1980s.
Between February and March 1988, the GNLF shut down the hill region for 40 days in a row.
But the GNLF leader Subhash Ghising later settled for regional autonomy.
Late last year, a large group of the Gorkhas, led by his former lieutenant Bimal Gurung, split from him and formed the GJM to renew the struggle for a separate state.