Police are pursuing a group of black magic practitioners, suspected of assisting last week's vandalism at Phanom Rung castle in Buri Ram.

Local police in provinces bordering Cambodia are cooperating with taskforce officers to track suspected groups, and will apprehend them if they try to flee the country.

Provincial police chief Colonel Wichai Sangpraphai says the most likely group of suspects are possibly based outside Buri Ram. Village heads and civilian authorities are working with police to identify the suspects or track them.

A large number of local and foreign tourists visited the castle and the Phanom Rung historic park to see, from a distance, the damage done to the artefacts. The estimated number yesterday was around 10,000 - twice the normal figure before the incident.

Money spent by tourists has reached Bt4 million a day, up from between Bt1 million to Bt2 million beforehand.

Culture Minister Anusorn Wongwan says security has been beefed up at historic sites as an immediate solution. Installation of surveillance cameras is under consideration.

The ministry is researching the registration of the Phanom Rung castle as a World Heritage site.

Park chief Dusit Thummaphorn says repairs, which will take around one month, will cost around Bt30,000. They will start with the mouth of a mythical-lion figure. The most difficult repairs will be to the head of King Naga.