Hotels and restaurants in the Gaza Strip recently took everything off the menu except salt water in solidarity with the estimated 1,600 Palestinian prisoners currently on hunger strike to protest conditions in Israeli jails.

Staff at fifty establishments wore uniforms reading ‘salt and water’ and ‘honour for dessert’ during a day long stunt earlier this month, Salah Abu Hassireh, head of the Palestinian Committee for Restaurants, Hotels, and Tourist Services told local media.

Online, a social media campaign called the ‘salt water challenge’ has attracted the attention of millions after Palestinian pop star Mohammed Assaf downed a glass in a YouTube video, spurring on thousands more to take part.

Issa Qaraqe, head of detainees' affairs for the Palestinian Authority (PA), estimates that 1,600 are currently taking part in the strike, which began 17 April - Palestinian Prisoners’ Day.

The ‘Freedom and Dignity strike’ is over several issues ranging from access to telephones and lawyers, to better medical care, to ending solitary detention.

Around 6,500 Palestinians are currently detained in Israeli prisons, most for terrorism convictions, although Palestinian leaders and prisoners’ groups maintain that many have been unfairly tried or are political prisoners.

A further 500 are detained under what is known as Administrative Detention, which allows suspects to be held without charge for six month intervals.

Ground: Ten years of the Palestinian conflict in pictures Show all 10 1 /10 Ground: Ten years of the Palestinian conflict in pictures Ground: Ten years of the Palestinian conflict in pictures Neve Dekalim, Gaza Strip, 12 September, 2005. Thousands of Palestinians from nearby Khan Younes enter Neve Dekalim at dawn to see this former Jewish settlement for the first time. Most people tried to find anything still usable in the ruins of the settlement's buildings destroyed by the Israeli army. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Al Tufa'ah, Gaza Strip, 20 January 2009. Nadji Hessenin collapses in tears on his father's grave after burying his children Shourouk Nadji Hessenin, 13, and her brother Abdallah, 12, who were instantly killed upon returning to their house in She' Af Tufa'ah by a Hamas planted booby trap intended for Israeli soldiers. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Rafah, Gaza Strip, June 2010. Most if not all the goods sold in this busy market street in Rafah are brought from Egypt through the tunnel. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Ramallah, West Bank, 13 November, 2004. Sadness and emotion among the people who are coming to honour Palestinian President Yasser Arafat at his grave in the Muqata'a. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Qalqilya, West Bank, January 2003. The only entrance to the city. Palestinian population movements are severely restricted by the Israeli army, no vehicles being allowed in or out some Palestinian cities for weeks on end. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Jenin Refugee Camp, April 2002. In order to search for Palestinian activists, the IDF stormed and occupied the camp for nine days, razing an area the size of three football pitches in the centre of this densely populated zone, totally destroying 95 houses, damaging hundreds of others, leaving 3,000 people homeless. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Ousama Jawabreh, 29, was killed when a public phone he was using in the old quarter of Nablus city exploded on 24 June 2001. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Near Jericho, West Bank, July 2001. Most of the River Jordan valley is militarily closed to the Palestinians, allowing Jewish settlements to thrive on its water and natural resources. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Kfar Kila, South Lebanon, 29 May, 2000. After the Israeli pull-out, thousands of SLA (Lebanese militia financed and trained by Israel in the occupied zone) rushed to this last point of passage in order to escape Israel; abandoning their cars and many of their belongings. For weeks, clothes hanging on the border fence were the only remaining signs of many personal and family tragedies. © Bruno Stevens Ground: Ten years of the Palestinian conflict in pictures Ain el Helweh Palestinian Camp, 15 May, 2000. School children demonstrate on the 52nd anniversary of the Palestinian exile, the 'Neqbah' ('catastrophe'). © Bruno Stevens

The issue strikes a sympathetic chord across all sections of Palestinian society; according to Palestinian estimates, disputed by Israel, 750,000 people have at one point or another in the last 50 years been imprisoned by the Israeli state, affecting seven out of ten families.

There have been several hunger strikes mounted in the past, but never on so large a scale.

The Israeli authorities have condemned the protest. Shortly after the strike began Public Security Minister Gilad Erdan told Army Radio that the striking inmates were “terrorists and incarcerated murderers who are getting what they deserve.”

The current initiative is being led by Marwan Barghouti, a Palestinian leader jailed by Israel for life for five murders.

Barghouti, who is popular in both Gaza and the West Bank and is sometimes touted as a future successor to incumbent Palestinian Authority President Mahmoud Abbas despite his multiple sentences, has been placed in solitary confinement for his role in the strike.

Last week Israel’s prison service released surveillance video footage from 27 April and 5 May in which Barghouti was shown moving around inside his cell before allegedly eating cookies from an envelope, and a snack bar.

“This hunger strike was never about the conditions of the convicted terrorists, which meet international standards,” Mr Erdan said in a statement.

“Barghouti is a murderer and hypocrite who urged his fellow prisoners to strike and suffer while he ate behind their back.”

Israeli right-wing activists hold a barbecue outside Ofer military prison in the occupied West Bank, where a number of Palestinian prisoners are on a hunger strike (MENAHEM KAHANA/AFP/Getty Images)

Fadwa Barghouti, the leader’s wife, as well as the Palestinian Prisoners’ Club, have denounced the footage as doctored.

Barghouti's lawyer said on Sunday that his client denied the authenticity of the video, pointing out the cell shown was cleaner and bigger than the one he resides in.

A representative for the hunger strikers said last week that at least one faction is considering refusing water if their demands continued to go unmet.

Israel’s prison service has said it will set up a field hospital to treat hunger strikes if necessary.