A US aid worker kidnapped in Niger two days ago is likely being held by militants from the Movement for Oneness and Jihad in West Africa (Mujao), the country's interior minister said Sunday.

Mohamed Bazoum told AFP that the American, named as Jeffery Woodke, "was probably kidnapped by the Mujao or handed over to the Mujao by those who abducted him".

He said Niger's forces had followed the kidnappers across the border into Mali to a zone controlled by Mujao.