With his ministerial colleagues, especially from Bihar, venting their anger, Prime Minister Manmohan Singh, who chaired the meeting, revealed he has written a "strongly-worded" letter to Maharashtra Chief Minister Vilasrao Deshmukh and asked Home Minister Shivraj Patil to convey the collective strong sentiments of the union cabinet to the state government, sources said.

With Railway Minister Lalu Prasad not present at the cabinet meeting, it was Fertilizer Minister Ram Vilas Paswan who led the charge against Thakceray's campaign and wondered what the Centre was doing when national unity and integrity was being challenged.

He felt Thackeray was being made a hero by arrest-and-release "drama" of the state government and demanded that he be booked under NSA. He was supported by RJD's P C Gupta and Raghuvans Prasad and Congress' ministers P Chidambaram, H R Bhardwaj, Kapil Sibal and S Jaipal Reddy.

The Prime Minister is believed to have said that he shares the concerns of the allies and has written a strong letter to Deshmukh on Monday after a delegation of leaders from Bihar led by Chief Minister Nitish Kumar had met him.

What more could he do, he is believed to have asked.

The ministers with legal background Chidambaram, Bhardwaj and Sibal were understood to have favoured a judicial inquiry into the killing of the Bihari youth in a bus by Mumbai police on the ground that a civilian probe would not suffice.

Bhardwaj is understood to have pointed out that since allegations had been levelled against police in the case of killing of a youth from Bihar, a judicial or a magisterial inquiry would be appropriate.

Sibal and Reddy voiced concern over the violence against north Indians in Maharashtra, saying the developments did not send the right signals.

Patil told the meeting that his ministry had issued three advisories to Maharashtra government over the violence against North Indians and 56 cases were registered against Thackeray in connection with these incidents, the sources said.

When Patil said that his ministry had issued three advisories to Maharashtra, Paswan said if the state government still did not act to stop violence, the Centre should think about other options.

Pressing for Thackeray's arrest under NSA, Paswan said the MNS chief was getting out on bail in whatever cases had been filed against him.

He cited the case of MDMK chief Vaiko's arrest for his alleged statements in favour of LTTE and said why similar action should not be taken against Thackeray, the sources said.