Prime Minister Abdullah Ahmad Badawi has stood by his government's decision to use a tough security law to detain a Sri Lankan alleged to be involved in an international nuclear blackmarket.

Malaysian police detained Sri Lankan businessman BSA Tahir on Friday under the Internal Security Act (ISA).

Police immediately sent 44-year-old Tahir to the Kamunting detention centre in Perak. The ISA allows for two-year detention periods which can be renewed indefinitely.

"Yes, we used the ISA for this case. The reason we use the ISA is because it is an issue of the security of Malaysia," Abdullah, who is on an official visit to China, told reporters over the weekend.

Abdullah, who is also the internal security minister, said the investigation into Tahir was continuing.

He was arrested on suspicion of involvement in an illicit nuclear network run by Pakistani scientist Abdul

Qadeer Khan.

Middleman

The United States on Friday hailed the arrest, saying it could be a breakthrough in global efforts to dismantle Khan's nuclear network.

Khan, a one-time national hero credited with making Pakistan a nuclear power, has admitted selling nuclear secrets abroad but was pardoned by President Pervez Musharraf.

Tahir is married to a Malaysian and split his time between business interests in Kuala Lumpur, where he has a home, and Dubai.

He has admitted to police that he acted as a middleman for Khan, and gave details of the proliferation scandal, according to an official Malaysian police report handed to the International Atomic Energy Agency in February. - AFP