Chennai, May 27 (PTI): Accusing Kerala of preventing Tamil Nadu from closing the holes drilled in the Mullaperiyar dam, chief minister Jayalalithaa on Sunday sought the immediate intervention of Prime Minister Manmohan Singh to facilitate the work and demanded deployment of CISF at the site.

In a letter to Singh, she warned that if the Kerala government persisted with its "recalcitrant" attitude and if the Centre did not deploy CISF personnel, Tamil Nadu police would be stationed to guard the dam.

She said the vertical holes were drilled as part of the core stability test ordered by Supreme Court appointed Empowered Committee headed by Justice AS Anand to study the safety aspects of the century-old dam, over which Tamil Nadu and Kerala are locked in a dispute.

It was necessary to fill the holes before the onset of the monsoon so as to prevent any damage to the dam, located in Idduki district of Kerala but under the control of Tamil Nadu.

However, the Kerala government had been preventing Tamil Nadu officials from closing these drilled holes, in spite of the clear directions given by the Empowered Committee and the matter was taken up by her government with the neighbouring state but to no avail, she said.

The two states are locked in a dispute over raising water level in the dam, which irrigates five southern districts in Tamil Nadu.

While Kerala has been pressing for a new dam to replace the existing old structure on safety grounds, Tamil Nadu has opposed it and moved the Supreme Court.

Jayalalithaa claimed that the Kerala government's attempt to prevent closing of the holes appeared to be a ploy intended to ensure that dam's structural stability was weakened, especially in the light of the Empowered Committee's conclusion that the dam was safe and water level could be raised to 142 ft.