Hundreds of fish and other sea creatures at an aquarium on Malaysia's tourist resort island of Langkawi were deliberately poisoned, officials and police said Wednesday.

Haizol Sam, marketing officer at Underwater World Langkawi, said about 600 marine creatures -- including fish, stingrays, barracudas and sharks -- were found dead in their tanks around closing time Monday.

"The police investigations concluded there was sabotage. The tanks were contaminated with some sort of poison which has yet to be identified," Haizol told AFP.

Langkawi police chief Mohamad Ali Jamaluddin said initial investigations showed the fish were poisoned by a petroleum-based substance.

"We smelled petrol near the tanks and believe it was the work of more than one person," Mohamad Ali was quoted saying by the official Bernama news agency.

The dead creatures were among some 4,000 kept at the aquarium on the island off northern Kedah state, reportedly the largest in Malaysia.

Haizol said police investigations were continuing.