The largest study to date on links between mobile phone use and certain types of brain cancer has proved inconclusive, researchers say.
The results indicate a possible health risk from heavy mobile phone use, said the World Health Organisation (WHO), which conducted the study.
But it said further research was needed for more conclusive answers.
The 10-year study of 13,000 people has been criticised because mobile phone companies provided 25% of the funding.
“The study doesn’t reveal an increased risk, but we can’t conclude that there is no risk because there are enough findings that suggest a possible risk,” the study’s chief author, Elisabeth Cardis, told AFP news agency.