The armed branches of Hamas and Palestinian Islamic Jihad in Gaza have emphasised joining forces to carry out attacks against Israel, Hamas\' military spokesmen announced. Abu Ubaida, a spokesman for Hamas\' Ezz Eddine Qassam Brigade, said in a TV interview that the need to fight Israeli occupation and resist its \"divide and conquer\" policy brought his movement strategically closer to Islamic Jihad. Abu Ubaida said that the two movements have never stopped coordination between them and this coordination was meant both as a message of unity to Palestinians and as a deterrent to Israel. The two movements claimed joint responsibility for at least 50 mortar shells fired into southern Israel Monday morning. Israel retaliated by targeting Hamas outposts in Gaza. The Monday attacks marked the first time since June that Hamas had claimed responsibility for firing into Israel. In the past, Hamas has tried at times to dissuade the Islamic Jihad -c onsidered politically less pragmatic - from firing at Israel, fearing Israeli retaliation. However, Abu Ubaida stressed that Hamas will never consider halting \"military resistance\" and will always keep in touch with other Palestinian military factions in that regard, adding that the decision to launch attacks on Israel or suspend is only depending on \"what we think is good for the Palestinian people.\" Abu Atiya, the spokesman of a third armed faction in Gaza - the Salahuddine Brigades- suggested Wednesday establishing a joint command center with Hamas and Islamic Jihad to coordinate military retaliation to the Israeli occupation\'s attacks. Hamas took control of the Gaza Strip from the Fatah-led Palestinian Authority in 2007. Since then, Israel said it holds Hamas responsible for all attacks from Gaza, whether claimed by the Islamist movement or not.