LONDON - (AFP) - The family of imprisoned dissident Alaa Abdel-Fattah has called on British Prime Minister Rishi Sunak to intervene in his case during his participation in the COP27 climate summit in Egypt next week.

Abdel-Fattah is on hunger strike and warned his relatives that if he is not released during the summit, he will probably die in prison because he will stop taking fluids from Sunday, the opening day of the twenty-seventh session of the Conference of the Parties.

Abdel Fattah, a prominent figure in the 2011 revolution that overthrew President Hosni Mubarak, is serving a five-year prison sentence for "broadcasting false news", and he has spent a large part of the past decade in prison.

He was granted British citizenship in prison in April through his British-born mother.

Cairo has faced repeated criticism of its human rights record since announcing last year that it would host the COP27 climate summit, a move that rights groups said "rewarded the repressive rule" of President Abdel Fattah al-Sisi.

"I want to invite Rishi Sunak to intervene" in my brother's file, Sanaa Seif, one of Abdel-Fattah's sisters, told reporters in London.

"You will meet Sisi... and if you don't show interest, he will interpret it as a green light to kill him," she added.

Sana explained that the family received a phone call from British Foreign Secretary James Cleverly on Wednesday and met Thursday with British Minister of State for Foreign Affairs Tariq Ahmed.

Another sister, Mona Seif, added that if her brother is not released during the climate conference, he will surely "die in prison."

She added that her brother was eating only 100 calories a day in the form of a spoonful of honey and a little milk in his tea and would start a hunger strike on Sunday.

In an open letter published Wednesday, 15 Nobel laureates called on Egypt to release Abdel Fattah.

More than 90 heads of state and government are scheduled to participate in the summit, which will be held in Sharm el-Sheikh resort from 6 to 18 November.

Human rights organizations estimate that about 60,000 political prisoners are languishing in Egyptian prisons, many of them in harsh conditions and overcrowded cells, accusations Cairo denies.