DAKAR, Senegal (AP) — An Islamic State group offshoot is claiming it carried out the October attack in Niger that killed four U.S. soldiers and four Nigerien troops and sparked questions about U.S. military involvement in West Africa's vast Sahel region.

The Mauritanian Nouakchott News Agency reported Friday that Abu al-Walid al-Sahrawi with the self-professed IS affiliate claimed responsibility for the Oct. 4 ambush about 120 miles (200 kilometers) north of Niger's capital, Niamey. The news agency has carried messages from the affiliate before, according to the SITE Intelligence Group, which...