NEW DELHI, Jan. 5 (Xinhua) -- Indian police have booked the chief minister of eastern state of West Bengal on charges of making inflammatory speeches over a citizens' register exercise being carried out in the northeastern state of Assam, a police official said Friday.

"West Bengal's Chief Minister Mamata Banerjee has been booked under Section 153(A) of Indian Penal Code, which pertains to promoting enmity among groups on grounds of religion, race, place of birth, residence, language and for disrupting harmony," the police official said.

The police case was filed Thursday, a day after Banerjee criticized the citizens' register exercise at a political rally in her home state and alleged that it was a conspiracy to drive out Bengalis from Assam by "excluding" their names from the registrar.

India's ruling Bharatiya Janata Party, which governs Assam, has also slammed Banerjee.

"What she (Banerjee) said is unbecoming of a chief minister and is an insult to the Supreme Court, which is monitoring the National Register of Citizens updating exercise taken up by the Registrar General of India," Assam's Industries Minister Chandra Mohan Patowary said Thursday.

"Our government has taken utmost care to ensure a smooth updating exercise, but her party and others are unhappy that there has been no violence or communal tension to cash in on," the minister added.

Illegal immigrants from the neighboring country of Bangladesh have long been accused of entering Assam and grabbing land, a contentious issue plaguing the state for a long time.