Switzerland has imposed new controls aimed at combating the trade in so-called "conflict diamonds". The measures are in response to United Nations criticism that Switzerland is a major centre for the trade in illicit gems.
The new controls, which include a tightening of the customs regime, are intended to prevent the trafficking in diamonds, which are helping to fuel the civil wars in Angola and Sierra Leone.
In December, Switzerland was identified by the United Nations as one of the main centres for the trade in illicit diamonds. The accusation prompted the government to impose the new restrictions, which go beyond the guidelines laid down by the UN.
The government said on Wednesday that, under the new measures, all shipments of diamonds moving through Swiss customs warehouses will have to be declared, and details provided about their country of origin.
Officially, Switzerland imports very few uncut diamonds. Yet reports suggest it has been an important transit point for these rough stones. For example, some 41 per cent of the rough diamonds imported into Britain in 1999 were declared as being of Swiss origin.
Part of the reason for this is that the free ports at Zurich and Geneva airports are thought to have been used to "launder" stones of dubious origin. The new rules are intended to prevent these ports being used for that purpose.
"By putting the transit of rough diamonds from Sierra Leone through customs warehouses under prohibition, Switzerland has gone beyond what is required by the United Nations," Roland Vock, a spokesman for the State Secretariat for Economic Affairs (Seco), told swissinfo in a recent interview.
Seco is also expanding the number of "sensitive" African countries, which are thought to act as transit countries for illicit diamonds from Sierra Leone. The list will be increased from seven to 15 states.
The United Nations Security Council has banned the import of diamonds from Angola and Sierra Leone because rebel groups there are using gems mined in areas under their control to finance their wars.
Last July, the UN Security Council passed a resolution placing an embargo on all diamonds from Sierra Leone, which did not have a UN-approved certificate. It imposed a similar ban on diamonds coming from areas controlled by Unita rebels in Angola in June 1998.
swissinfo with agencies