Hong Kong Customs agents have made a record seizure of the party drug ketamine and arrested four Singaporeans and three Malaysians, officials said on Tuesday.

In an operation at the Hong Kong International Airport and other locations in the Chinese enclave Sunday and Monday, authorities seized 87.5 kilograms of high-grade ketamine with an estimated retail value of US$3.8 million, the government information service said in a statement.

The statement said they had "smashed a transnational ketamine syndicate."

Timothy Tong, Commissioner for Customs and Excise, said he "could not rule out" that the drugs were destined for mainland China.

"Intelligence revealed an emerging trend of smuggling ketamine into Hong Kong and the mainland from sources in Southeast Asian countries, particularly India and Malaysia, as evidenced by the seizure of 94.7 kilograms of ketamine up to now in 2005 compared to the total seizure of 4.8 kilograms in 2004," the statement said.

It did not name the suspects but said they will be charged with trafficking in dangerous drugs, which carries a maximum prison term of life.

According to the US Drug Enforcement Administration, ketamine is a tranquillizer commonly used on animals and which is popular among nightclubbers.