British hostage John Cantlie believes 'two-thirds' of what he says in IS videos

The sister of British journalist John Cantlie, who has been taken hostage by the Islamic State (IS), has reportedly said that her brother probably believes "two-thirds" of what he is saying in the propaganda videos released by the group.

Cantlie, who was captured by the militants nearly two years ago, has appeared in a series of videos released by the IS in recent weeks in which he speaks about the group and criticizes both the United States and the United Kingdom governments for their strategies to deal with the terror group, reported The Independent.

The photojournalist is shown dressed in an orange jumpsuit and appears to be reading from a prepared script each time. He has said that it is true that he is a prisoner but has claimed that he has been abandoned by the Government.

His sister, Jessica, issued a plea last week urging his captors to renew contact with her family.