A British-US national detained by Iran has gone on hunger strike, his sister has said.
Wildlife conservationist Morad Tahbaz, 66, who also holds Iranian citizenship, was taken back into custody after originally being allowed out on furlough on the same day last week that charity worker Nazanin Zaghari-Ratcliffe and retired civil engineer Anoosheh Ashoori were released and then allowed to return to Britain.
