Updated

A U.N. study based on interviews with nearly 500 African recruits to extremist groups says the majority were poor, marginalized and finally tipped into joining because of perceived government violence or abuse of power.

The two-year study by the U.N. Development Program found that recruitment by groups in Africa such as Boko Haram and al-Shabab occurs mainly locally on a person-to-person basis — not online as in other regions.

It says 80 percent of the 495 recruits interviewed joined within a year of being introduced to an extremist group and nearly half joined within just one month.

The U.N. agency's Africa director, Abdoulaye Mar Dieye, says: "This study sounds the alarm that as a region, Africa's vulnerability to violent extremism is deepening."

The report was released Thursday.