Palestinian officials say leaders of prisoners in Israeli jails have launched a hunger strike, demanding better conditions.

Qadora Faris, head of Palestinian Prisoners Club, said on Monday that 30 inmates in Israeli jails have refused their meals as part of the strike, and that hundreds more plan to join.

The Israel Prison Service says it's prepared for any scenario but that it isn't aware of any mass hunger strike by Palestinian inmates.

At the root of the prisoner protest is an Israeli crackdown on cellular phones smuggled into the prisons, and electronic jammers used to disable them. The prisoners are also protesting alleged mistreatment by Israeli guards, including regular searches of cells for phones.

The hunger strike begins a day before Israel heads to the polls for national elections.