Protests against plans to carve out a new state in India's southern Andhra Pradesh state have led to sporadic violence.

A strike is being held in 12 districts and protesters have attacked public transport vehicles in some places.

The move to form Telangana state has plunged the state into political crisis. Over 100 lawmakers have resigned from the assembly.

The move is also fuelling demands for other new states across India.

Two parties in the eastern West Bengal state have said they will begin campaigningagain for separate states.

The Gorkha Janmukti Morcha (GJM) is demanding a separate state and fairer treatment for Darjeeling's Nepali-speaking Gorkha community.

And the Kamtapur Peoples Party (KPP) is demanding a separate state for the local Koch-Rajbongshi people.

The GJM has announced a four-day strike in the Darjeelingregion beginning Monday.

The KPP has said it will set up roadblocks on highways in northern Bengal, which connect India's seven north-eastern states to the mainland.

"We will join the Gorkhas in the movement for a separate state. It is now or never," said KPP chief Atul Roy.

A spokesman for the Bodo tribespeople in the north-eastern state of Assam has also

demanded the creation of a separate state.

"We welcome the creation of Telangana and we hope the Indian government will take necessary steps to create a separate Bodoland state without any further delay," said Sangsuma Khungur Bwismutiary, the independent Member of Parliament from Kokrajhar, die headquarters of the Bodoland Territorial Council.

The BBC's Soutik Biswas in Delhi says the announcement of a Telangana state has come as a shot in the arm for political parties and groups in the country demanding news states.

Reports say that the federal government is already sitting on proposals for nine new states in the country.

Telangana region is spread over 10 northern districts of Andhra Pradesh.

The demand for separate state status for the underdeveloped and drought-prone area dates back 50 years.

More than 400 people died in violence over the demand for a Telangana state in 1969.

Campaigners say Telangana's economic development has been neglected in favour of the richer and more powerful Andhra region -and that a new state is the only solution.

The last three new states in India were formed in 2000: Chhattisgarh was created out of eastern Madhya Pradesh; Uttarakhand was created out of the hilly areas of northern Uttar Pradesh, and Jharkhand was carved from Bihar’s southern districts.

India currently has 28 states.