DUBAI, United Arab Emirates (AP) — A United Nations group has criticized Bahrain for arbitrarily arresting three members of the family of a prominent exiled activist.

The U.N.'s Working Group on Arbitrary Detention in a report dated Monday focused on the cases against the family members of Britain-based activist Sayed Alwadaei of the Bahrain Institute for Rights and Democracy.

The group found that Bahrain arbitrarily detained the three without warrants and didn't give them the right to a fair trial. The group said it encountered similar cases on the island nation off Saudi Arabia. It warned systematic deprivation of citizens' liberty "may constitute crimes against humanity."

The group said Bahrain denied the allegations, but offered no evidence to support its claims.

Bahrain, home to the U.S. Navy's 5th Fleet, has cracked down on dissent for years.