Two caravans used in the shooting of Mani Ratnam's multilingual movie "Ravan", starring Abhishek Bachchan and Aishwarya Rai, in Ooty have been seized for having forged vehicle documents, police said Tuesday.

The two caravans had the same registration number. "An investigation led to findings of fraud in the use of forged vehicle IDs and tax evasion, which in turn led to seizure of four vehicles during the last week, " a police official told.

According to police, the vehicles seized in Ooty, some 550 km southwest of here, have been valued at Rs.12 million. Both Abhishek and Aishwarya are said to have used the vehicles during the shooting.

The shooting of 'Ravan' has been shifted to another hill station, Hogenekkal (some 300 km southwest of here).

The police official said he feared the "racket may be much bigger since all top stars use high-priced caravans".

Police teams have left for Mumbai and elsewhere in Tamil Nadu to look for other similar vehicles.

Sources close to Ratnam said: "To our knowledge only two vehicles that were being operated for us have been seized. The suppliers who lent logistical support to our outdoor units should be blamed. Our shooting is in progress without any glitches."

"Our office has taken up the issue with the suppliers, " the source added.

"Ravan" is being made in Hindi and Tamil. It also stars Tamil actors Vikram and Karthik. Since shooting began last year, minor problems have dogged the venture, including Ratnam being laid down with a mild heart problem, and cinematographer Manikandan handing over the work to another celebrated cameraman Santosh Sivan.