Police in Belgium, Switzerland and France have arrested 31 people in connection with a large robbery of diamonds at Brussels airport in February.
Belgian prosecutors say large sums of money and some of the diamonds have been recovered.
One suspect was arrested in France and six in Switzerland on Tuesday. The other 24 were arrested near Brussels early on Wednesday.
A gang broke into the cargo hold of a Swiss aeroplane as it waited for take-off on the evening of Monday, 18 February.
They took 120 packages of "rough stones" worth $US50 million, being transported from Antwerp to Zurich and escaped through a hole in the perimeter fence.
Prosecutors said the whole operation took only about five minutes. No shots were fired and no-one was hurt.
The BBC reports Antwerp is the hub of the world diamond trade - about 150m euros worth of stones move in and out of the city every day.