bamenda cameroon least 17 people die clash security force protesters cameroon english-speaking regions amnesty international say violence break area separatist movement gather strength clash begin sunday local group call protest say marginalization francophone-dominated government country long-time ruler paul biya witness say security force open fire often close range ilaria allegrozzi amnesty international lake chad region researcher tell reuters victims die across several towns two anglophone regions border nigeria worry escalation witness weekend reach crisis point allegrozzi say local mayor confirm one victims 13-year-old girl die bullet wound sisiku ayuk tabe leader separatist movement call govern council ambazonia say final death toll likely exceed 30. government officials respond request comment daytime curfew place city bamenda monday security force set barricade along virtually empty avenues reuters witness saw police wear balaclavas beat detain young man resist arrest cameroon today oil cocoa producer population 23 million people rule germany end world war one divide french british victors deep cultural linguistic divide spur protest great autonomy nearly year ago authorities respond lock opponents cut internet access government france monday call side reject violence opposition leader john fru ndi run biya past elections say president might struggle ease tensions next year election 84-year-old biya hold power since 1982 expect seek another term solutions available miss chance say interview home bamenda monday biya condemn late outbreak violence least 17 kill cameroon separatist clash amnesty