The United States is offering rewards of up to $18 million for information leading to the capture of four Islamist militants operating in north and west Africa.
The State Department said Friday the four were all involved in either the kidnapping of foreigners or attacks on Western targets.
It says three of the men have ties to the group al-Qaida in the Islamic Maghreb, which operates across a region that includes Nigeria, Niger and Mauritania.
It describes two of those men (Hamad el Khairy and Ahmed el Tilemsi) as founding leaders of the group Movement for Unity and Jihad in West Africa, and the other (Khalid al-Barnawi) as a former member of the Nigerian Islamic group, Boko Haram.
Also on the list is an Egyptian explosives expert (Abu-Yusuf al-Muhajir) who the State Department says planned attacks on U.S. targets in Egypt.