The country's gun regulator has recently registered about 427,000 weapons - almost 463,000 fewer than before the reform, Belgian newspaper Le Soir reported. While more than 125,000 were handed in as the new law came into effect, the remainder appear to have slipped through the cracks.

“They exist somewhere, but nobody knows where exactly and who owns them,” Philip Ide, head of the federal arms department, told the newspaper.

Guns are strictly controlled in Belgium, available only by permit. Private possession of handguns is permitted only with special authorization, which is said to be extremely hard to get.