OpinionInsurgency in Mali must be tackledSahelian 'terrorists' threaten oil and gas rich West AfricaUrgent problem: (from left) Ivory Coast Prime Minister Patrick Achi, Togo President Faure Gnassingbe, Benin President Patrice Talon and Ghana President Nana Akufo-Addo talk during a counter-terrorism gathering in AccraPhoto: AFP/SCANPIXIain EsauLondon