GLOBAL online retail giant Amazon has threatened to fire employees for speaking out on environmental issues, A US-based workers’ campaign group has revealed.

Amazon Employees for Climate Justice (AECJ) said that workers were told on Thursday that they were in violation of company policy after they joined calls for it to do more to tackle climate change.

In a statement, the environmental group said some employees had been contacted by Amazon’s legal and human-resources teams and questioned about their public comments.