A charity that supports prisoners’ rights has started legal action to make the British government disclose the identities of two men that British forces detained in Iraq and sent to U.S. custody in Afghanistan, according to the Associated Press.

The organization, Reprieve, said it wants to identify the two men, who were picked up in 2004, and get approval from their families to pursue further legal action on their behalf. The British government says the United States claims that both men belong to a Pakistani militant group, Lashkar-e-Taiba. The British Military of Defense confirmed August 17 that it had received a letter from the charity’s lawyers and will respond “in due course.”