Jailed British-Egyptian activist Alaa Abdel Fattah has stopped drinking water as he steps up his hunger strike to coincide with the start of the COP27 summit, his sister has said.
Calls for his release escalated after the climate summit opened in Sharm el-Sheikh in Egypt on Sunday.
The 40 year old has consumed just 100 calories for more than 200 days to push Egypt to allow him UK consular access.
UK PM Rishi Sunak has said he will raise the issue at the COP summit.
Abdel Fattah, a key activist in the 2011 Arab Spring, is currently serving a five-year sentence for spreading false news.