Hamas new chief supports hunger-strike amid 'Israeli psychological-warfare'
Haniya, who was chosen by the party as its new leader on Saturday, said the Islamist movement stood with the hundreds of prisoners on hunger strike in Israeli jails.
"This visit is a message to our heroic prisoners that your cause was and will remain a top priority," he said during a visit to a protest in support of the strikers in Gaza.
"Your freedom is a national duty and your dignity is our dignity," the 54-year-old added.
Haniya's remarks came following Israeli reports of a video released by Israel's prison service allegedly showing the leader of the three-week strike Marwan Barghouti breaking the hunger strike.
On Sunday, Israeli authorities distributed video footage purporting to show Barghouti secretly eat in his cell.
Prison services said Barghouti was filmed eating cookies in secret on April 27 and May 5. They did not give any further information as to how he may have obtained the food, but Israeli daily Haaretz reported that he may have been set up.
Barghouti's wife and other Palestinian officials dismissed the video as fake and an attempt to break the hunger strikers.
The head of the Palestinian Prisoners' Club, Qadoura Fares, called the video a fabrication, stressing Barghouti was being held in solitary confinement at Kishon prison and had no access to food.
"This is psychological warfare that we expected Israel to wage against the strike," he was quoted as saying by the Associated Press.
Around 1,500 Palestinians in Israeli jails have been refusing food since April 17.
The strikers have issued a list of demands including better medical services, family visits and more dignified detention conditions.
Some 850,000 Palestinians have been incarcerated since Israel's occupation of their territories 50 years ago, Palestinian leaders say.
Agencies contributed to this report.