By Ayanjit Sen BBC reporter in Delhi

India's Supreme Court has asked the central government and the government of the southern state of Karnataka to provide details of the volume of water released from the Cauvery river to neighbouring Tamil Nadu.

This follows Tamil Nadu's accusation that Karnataka released less than a third of the water it was ordered to release by the court.

The Supreme Court had ruled earlier this month that Karnataka must release about 1.25 billion cubic feet of water a day, forcing the state to seek Prime Minister Atal Behari Vajpayee's intervention.

The government's Cauvery River Authority (CRA), headed by the prime minister, later significantly reduced the quantity of water Karnataka had to release to Tamil Nadu.

Farmers in both states depend heavily on water in the Cauvery, which flows from Karnataka to Tamil Nadu, to irrigate their fields.

Damaged sluice gates

Tamil Nadu has complained for years that Karnataka is holding up water with its dams and preventing the natural flow of the Cauvery.

Correspondents say by demanding information from both the central and state governments, the Supreme Court could be embarrassing the executive branch.

Karnataka farmers refuse to share water

Karnataka's Irrigation Minister, HK Patil, said his state would provide the details but Karnataka would not jeopardise its farmers' interests by releasing more water than the CRA has asked it to.

The next hearing of this case at the Supreme Court is scheduled on 23 September.

Hundreds of Karnataka farmers recently protested against the court order and damaged the sluice gates from which water was being released to Tamil Nadu.

Serious rioting

The dispute between the two neighbouring states over water-sharing has gone on for decades and has in recent years become a particularly sensitive issue.

A recent drought which reduced water supplies in many parts of India appears to have made the situation worse than before.

Karnataka state authorities say the farmers' action forced them to stop releasing water last week. They say the sluice gates are being repaired.

Local organisations in Bangalore, Karnataka's state capital, went on strike on Thursday in protest at the release of water to Tamil Nadu.

Eleven years ago, the dispute led to serious rioting in Bangalore and other parts of the Cauvery basin, leaving more than 25 people dead.