The Cauvery row hotted up today with Tamil Nadu deciding to knock Supreme Court's doors with a contempt petition for "unilateral" stoppage of water by Karnataka which rejected the charge of violating court order.

A day after Karnataka's action, the Jayalalithaa Government accused the upper riparian state of "unilaterally" stopping water release, saying it amounted to dishonoring the apex court order and impeding the country's federal structure.

Tamil Nadu's decision to intensify the legal battle came at a high-level meeting chaired by Chief Minister J Jayalalithaa even as protests showed signs of subsiding in Karnataka after water discharge was stopped citing depleted storage.

Karnataka last night stopped water release from the Krishna Raja Sagar dam, hours after Prime Minister Manmohan Singh made it clear only the Cauvery River Authority can review its order directing the state to release 9,000 cusecs to Tamil Nadu.

Rejecting Tamil Nadu's contention, Karnataka asserted that it has not committed contempt of court.

"There is no contempt of court. Karnataka's senior counsel Fali S Nariman yesterday brought to the Supreme Court's notice that the state is not in a position to release more water to Tamil Nadu", Shettar told reporters in Bangalore on his return from Delhi.

Shettar said he could not get an appointment with the Prime Minister with whom he wanted to plead for an early review of the CRA decision.

Meanwhile, UPA came under pressure from its key ally DMK with its chief M Karunanidhi virtually demanding imposition of Central rule in Karnataka state so that it served as a lesson to any "stone-hearted" regime on inter-state issues.

"All I request the Prime Minister is, (he) should come to a conclusion on using Article 356 (relating to President's rule) against Karnataka to ensure that the people of both the states uphold integrity and sovereignty in a spirit of brotherhood," Karunanidhi said in a statement.

On a petition from Tamil Nadu, the apex court had earlier endorsed the CRA ruling asking Karnataka to release 9,000 cusecs from September 20-October 15, a decision contested by both states, locked in the vexed Cauvery dispute.

Life in Mandya district, the hotbed of Cauvery politics, was limping back to normalcy after water discharge was stopped though farmers said they would continue their dharna till the CRA reviewed its September 19 directive.

"Till the CRA headed by the Prime Minister gives its verdict, we will continue the agitation", said M S Atmananda, former minister and leader of Cauvery Hitarakshana Samithi, spearheading the stir since water release began on Sept 30.

Police said they were continuing a tight vigil in the Cauvery basin area to prevent any untoward incidents.

In Tamil Nadu, CPI workers and farmers blocked trains in some delta districts demanding continuous release of water by Karnataka as per the CRA order.

Led by CPI National Secretary D Raja and party's state Secretary D Pandian, they blocked trains at different places including Thanjavur, Tiruvarur and Mayiladuthirai, police said, adding over 500 party workers were detained and later let off.