The execution of a kidnapped aid worker and the apparent death of a senior factional leader have sparked fears of an upsurge in Boko Haram violence in northeast Nigeria.
The International Committee of the Red Cross (ICRC) on Monday announced that one of its employees, midwife Saifura Khorsa, had been killed after more than six months in captivity.
That followed reports last week that hardliners in the Boko Haram splinter group Islamic State West Africa Province (Iswap) had killed their de facto leader, Mamman Nur.
Recent weeks have seen a marked increase in Iswap attacks on the military, which security analysts tracking the conflict said was a sign of renewed strength and organisation.