Two Myanmar men accused of killing two British backpackers on a Thai holiday island have retracted their confessions, their lawyers said on Wednesday, adding further confusion to an investigation that has attracted widespread criticism.

The retractions also come amid growing diplomatic concern that the two accused may have been abused during interrogation. Thailand's human rights commission said it would launch an inquiry into allegations of police torture.

The bodies of Hannah Witheridge, 23, and David Miller, 24, were discovered on Sept. 15 by cleaners on a beach on Koh Tao, an island in the south of Thailand famous for its diving. Post-mortem examinations showed both suffered severe head wounds and Witheridge was raped.