Thousands rallied in the West Bank's two largest cities in support of four long-term hunger strikers, as the Palestinians demanded tougher EU action to help their prisoners. The deteriorating health of prisoners on hunger strike in Israeli jails has sparked several mass protests across the Palestinian territories, some of which resulted in clashes with the army. On Monday, more than 1,000 people joined a rally of support in the northern city of Nablus, while another 1,500 gathered in the centre of Hebron in the south to demand their release. Dozens of Palestinian youths also blocked the entrance to the UN offices in Ramallah, but Palestinian police prevented them from entering the building, correspondents said. With public anger growing over the fate of the prisoners, Palestinian negotiator Saeb Erakat wrote to EU foreign policy chief Catherine Ashton urging action, not words, to improve treatment of prisoners and secure their release. "We believe it is no longer acceptable to merely request better treatment of Palestinians in Israeli occupation prisons, but to demand an end to the arbitrary system of Israeli detentions," Erakat's letter said.