By Nidal al-Mughrabi BEIT LAHIYA, Gaza Strip, Feb 6 (Reuters) - Brothers Ismail and Muaeen Mdaires have every reason to hope Fatah and Hamas reach a deal in Mecca to end Gaza's factional warfare. Ismail is an officer in Fatah's elite Force 17. Muaeen is a Hamas activist. Despite their political differences, they agree it would be a disaster if Palestinian President Mahmoud Abbas of Fatah and Hamas leader Khaled Meshaal failed to put an end to fighting which has killed at least 90 people in Gaza since December. "The incidents that happened were unfortunate and they affected us all. The Zionist enemy was the only winner of the internal fighting," Ismail said. "We have reached a stage where we forgot about our enemy (Israel), and Hamas and Fatah were busy seeing who was stronger and who could kill or abduct more," he told Reuters as he sat next to his brother. Inside Ismail's small apartment, not far from a site of regular recent clashes, the brothers' children played around them. Muaeen lives in another flat in the same building. The Mdaires split reflects political divisions across Palestinian society, including within many families. Their 65-year-old mother Suhaila said the brothers talk about their differences at home, but "it is forbidden that they exceed the point of talking". "I am not happy about the fighting, it is forbidden," said the mother of 11, wearing a traditional black dress and white headcover. "I ask the big men meeting in Mecca to reconcile. I pray for them to reach an agreement." Like many others in the Gaza Strip, the Mdaires family was displaced from Hebria, a nearby town just visible from Gaza, in the 1948 Israeli-Arab war. The brothers said they joined Hamas and Fatah to fight Israel, not themselves. "We discuss things but we have reached an understanding between one another that fighting means that everyone loses," Ismail said. JAILED TOGETHER Ismail, 42, spent three years in an Israeli jail between 1988 and 1992. Muaeen, 38, was jailed for two years and was in the same prison as his brother for part of his sentence. In the past, the two men used their divided loyalties to help resolve local differences between Palestinian factions. "Hamas, Fatah and others used to meet in my home and the problems got resolved here," Ismail said. "I used to talk to my brother and to officials in Hamas to help end problems before they escalated." Their family bonds were tested when a nephew was abducted by a Fatah group who suspected he was from Hamas. They agreed eventually to seize a member of a Fatah family, saying they were forced to do this after peaceful means failed to free him. "We acted as a family, and not as factions, in order to prevent any spread of the clash," said Muaeen. "We swapped the one we abducted for our nephew and the incident ended." The brothers said they hoped that even if Abbas and Meshaal failed to agree on a unity government which could end a crippling Western embargo, they could at least end the fighting. But Ismail said the outlook was not promising. "There are some people among the two sides that are not willing to reach an agreement and that is what makes me less optimistic they would agree in Mecca," he said. His brother said failure at the talks in Saudi Arabia, which many Palestinians regard as a last chance to avoid civil war, would be catastrophic. "These have been black days in the history of the Palestinians," said Muaeen, cautioning that continued violence "would affect the social bonds among families". "We as Fatah and Hamas are either brothers or cousins or neighbours, therefore, we must find a way to agree," Ismail said.