Singapore on Wednesday denied claims by a Malaysian rights group that it used a brutal “coup de grace” to finish off botched executions and ordered Yahoo and other sites to correct reports of the matter.

The Malaysia-based Lawyers for Liberty alleged last week that Singapore prison officers had been instructed to manually break the necks of prisoners if the rope used to hang them broke during executions.

This was done by kicking the back of the prisoner’s neck, said the group, which based its report on information from an anonymous prison officer.