PREAH Sihanouk province customs officials prevented the export of several thousand tonnes of sand to Singapore in a recent raid, officials from the company transporting the material said Monday, adding, however, that it had obtained permission from the government to operate.

Pen Pinith, a supervisor at the Cambodia-based company Dany Trading, said company ships entered waters off of Preah Sihanouk province on August 14 after obtaining permission to carry the sand to Singapore.

He said the ships were raided on Friday, noting that employees aboard the ships had failed to produce official approval documents.

Prime Minister Hun Sen in May announced a ban on sand-dredging for export. In subsequent announcements, he said that dredging could be permitted in areas where damage to the environment could be minimised.

Pen Simon, director of the Customs and Excise Department at the Ministry of Economy, could not be reached for comment Monday.

Sao Sokha, commander of the national Military Police, said he had not yet received a report from officers involved in the raid.

Hundreds of thousands of tonnes of sand from the Kingdom's rivers and coastal areas have been dredged and shipped to Singapore for use in land-reclamation projects.

Indonesia and the Philippines are among the countries that have banned the practice of dredging because of its destructive impact on riverbeds and shorelines.