15 people have died in clashes between security forces and protesters in the English-speaking regions of Cameroon, Amnesty International has said.

Violence broke out on Sunday after local groups called protests against “marginalization” by President Paul Biya’s Francophone-dominated government. Eyewitnesses said security forces opened fire, often at close range.

“I now have confirmation of at least 15 killed in several towns,” Amnesty International’s Lake Chad region researcher, Ilaria Allegrozzi, told Reuters.