A military spokesman says a radical Muslim sect in Nigeria's northeast has shot and killed an on-duty soldier charged with guarding a market.

Lt. Col. Hassan Mohammed said Thursday that the soldier was fatally shot after he walked away from his post late Wednesday night to talk to civilians nearby.

Mohammed said a suspected member of the Boko Haram sect pulled a Kalashnikov rifle from his robes and opened fire, hitting the soldier in his chest and head.

No arrest had been made in the killing Thursday.

Boko Haram has claimed responsibility for a string of assassinations and bombings in northern Nigeria in its campaign to implement strict Shariah law in Africa's most populous nation.