DMK president M. Karunanidhi Tuesday urged Prime Minister Manmohan Singh to decide on imposing president's rule in Karnataka, a day after the state stopped supplying Cauvery river water to Tamil Nadu.

In a statement Tuesday, Karunanidhi said: "In order to protect the national integration, a final decision has to be taken on imposing Article 356 of the Constitution (president's rule) in Karnataka."

Karunanidhi said he was making the request with teary eyes so that farmlands in Tamil Nadu did not turn into graveyards.

He said a proper lesson had to be taught to the Karnataka government so that in future, no other state dared to cheat another state.

Karunanidhi said that while Tamil Nadu was taking up the issue in a peaceful and legal manner, the attitude of the Karnataka government went against all those who stressed on India's national integration.

Karunanidhi also criticised External Affairs Minister S.M. Krishna for writing a letter to Prime Minister Manmohan Singh to stop the release of Cauvery water from Karnataka to Tamil Nadu.

"A person in the union ministry should be impartial to two states. It is wrong to act in a parochial manner for political reasons," Karunanidhi, a former chief minister of Tamil Nadu, said in a statement Tuesday.

Referring to Manmohan Singh's Sep 19 order as chairman of the Cauvery River Authority (CRA) to Karnataka to release 9,000 cusecs of Cauvery water to Tamil Nadu, Karunanidhi said Krishna was wrong in writing to the prime minister urging him to stop the release of water.

Krishna, a former chief minister of Karnataka, in the letter, urged the prime minister "to explore possibilities of stopping further release of water from dams in Karnataka".

"I sincerely feel that the situation needs your immediate attention, if it is to be prevented from worsening, as there is already a strong feeling among people of Karnataka that they may have to face severe shortage of water in the months to come," Krishna wrote.