Shortly after Saturday's match kicked off in the Stade Roi Baudouin, heavy rain began to fall as Belgium pressed for an early opener.
Such a goal was not forthcoming, and midway through the half heavy hail began to fall.
Eventually the storm became too strong, with Kassai taking the players from the field in the 23rd minute, fearing for their safety with stones the size of golf balls beginning to bounce off the turf.
The players returned to the pitch and action resumed after a delay of more than 45 minutes.
With the stones large enough to turn an ankle on, both teams will have been grateful to Kassai for his decision.
The hosts will have been especially thankful, as they fly out to Brazil to begin their FIFA World Cup campaign, beginning against Algeria on June 17.
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