The Hamas premier in the Gaza Strip, Ismail Haniya, has been invited to the Non-Aligned Movement summit in Iran next week, his office said Friday, without saying whether he would attend. \"The prime minister has received a formal invitation from Iranian President Mahmoud Ahmadinejad to attend the non-aligned summit in Tehran,\" a statement from Haniya\'s office said. Palestinian president Mahmud Abbas, who heads a rival West Bank-based administration, said last month that he had accepted an invitation to attend. It will be Abbas\'s first visit to the Islamic republic. Haniya was there in February. Iran is a backer of the Islamist Hamas which has long been in conflict with Abbas\'s Fatah, and the Palestinian president has accused Tehran of trying to stymie attempts between the factions to reconcile. In April 2011, Abbas\'s Fatah and Hamas announced a surprise reconciliation and agreed on the creation of an interim cabinet of independents selected by the two factions, which would prepare for elections to take place by May 2012. But the deal has largely stalled, leaving presidential and legislative elections indefinitely postponed, although the Abbas administration has called for local authority elections in the West Bank in October. Over the past few days, Tehran has sparked a fresh wave of outrage in Israel after Ahmadinejad and supreme leader Ayatollah Ali Khamenei both described the Jewish state as a \"cancerous tumour.\" Israel and its ally, the United States, accuse Iran of seeking to develop an atomic arsenal, but Tehran insists its nuclear programme is for civilian purposes only. Israel, widely suspected to have the region\'s sole, if undeclared, nuclear arsenal, has warned that if need be it will attack nuclear facilities in Iran to prevent it becoming capable of producing nuclear weapons.