At least 18 people were killed in tribal clashes in Egypt on Saturday, security officials said, prompting police to send reinforcements to quell the unrest. The fighting between the Bani Hilal tribesmen and Nubian villagers in the southern province of Aswan was ongoing and the death toll was expected to rise, the officials said. On Thursday, the rival sides attended a reconciliation meeting aimed at ending long-standing disputes, but an argument broke out and became a firefight that killed three tribesmen, the security officials said.