Almost 1,400 Palestinians held in Israeli prisons are to go on hunger strike in protest at their detention conditions since a jailbreak last week, the Palestinian Authority said Tuesday.

Tensions have been running high since six inmates staged a dramatic escape from a high-security jail in northern Israel on September 6, via a tunnel dug under a sink. Four of them have since been recaptured.

Hundreds of their fellow inmates were transferred to other jails and personal items confiscated in searches carried out by guards, according to the Palestinian Prisoners' Club.

Angry prisoners started fires in several jails.

"The situation is very bad in the prisons, that's why they're going on hunger strike," Qadri Abu Bakr, head of the Palestinian Authority's commission for prisoners, told AFP.

He said 1,380 prisoners -- of more than 4,000 Palestinians held in Israeli jails -- were to start the strike action on Friday, to be joined by other inmates next week.

The Red Cross has said Israel has decided to allow visits to prisoners, after they were suspended last week. But Qadri expressed concern over the fate of the four escapees, whom the Red Cross has not been allowed to visit.