ABUJA (Reuters) - Two Nigerian soldiers were killed accidentally in an explosion in the central Plateau state on Saturday as they transported ammunition meant to be destroyed, a military spokesman said.
"Some of the unserviceable ammunitions exploded in the process of moving them to the demolition site in the bush," Colonel Sani Usman said on Facebook. "Unfortunately, two soldiers lost their lives and one sustained injuries."
Nigeria's military has been fighting a six-year insurgency by Islamist group Boko Haram which has killed thousands and kidnapped hundreds in a battle to establish a caliphate.
With help from armies in Chad, Niger and Cameroon, Africa's largest economy has sought to crush the group in the past two months, pushing them into what the army says is their last known stronghold in Nigeria's Sambisa Forest.
However, suspected Boko Haram militants crossed over from Cameroon on Friday and forced Nigerian troops out of the border town of Marte, one soldier told Reuters, indicating the group still has a reach beyond Sambisa.
"We retreated because we ran out of ammunition and until we are properly equipped, we can't do anything," the soldier said.
Another soldier said fighting had resumed.
Earlier this week, Nigerian forces backed by warplanes invaded Sambisa but soon retreated from the booby-trapped forest in northeast Nigeria, where intelligence officials believe hundreds of secondary school girls abducted a year ago were being held.
(Reporting by Isaac Abrak, Ardo Abdallah and Lanre Ola; Writing by Helen Nyambura-Mwaura; Editing by Ruth Pitchford)