Human Rights Watch said Wednesday it had evidence that Bahraini authorities abused human rights defenders arrested for protesting during the Formula 1 race in April.
Rights activist Naji Feteel, one of those detained, said he was subjected to electric shocks and waterboarding while in a Bahraini prison cell.
Director of Middle East programs for Human Rights Watch Sarah Leah Whitson said from Beirut that Bahrain's allies need to pressure the government to take rights concerns seriously.
"If the latest allegations are brushed aside it will be yet more evidence suggesting that Bahrain's justice system is a haven for torturers," she said in a statement.
The rights group reports that Bahrain's own investigation into the government's response to a 2011 uprising found that five detainees died as a result of torture while in custody.
Bahrain said it's committed to a series of reforms outlined by an independent commission probing the 2011 crackdown. Its allies, including the United States, have been criticized for taking a soft line on allegations of abuse in Bahrain.