While Niger will not be involved in any attempt to retake town from Boko Haram in their Border...
Niger has said it will not be involved in any attempt to retake the key north-east Nigerian town of Baga from the militant Islamist group, Boko Haram...
Bodies reportedly lay strewn on the streets of the town following an assault by the Islamists on Wednesday, with hundreds feared killed.
The town is near the border with Chad and had housed a military base staffed partly by multinational forces.
Soldiers from Niger had been there but were not present when it was attacked.
The BBC's Nasidi Yahaya in Abuja says the decision of Niger is clearly a big blow to Nigeria, which had said that the presence of a multinational task force in the area would help defeat Boko Haram.
The withdrawal of the troops from Niger means Nigeria's neighbour now has no forces directly involved in tackling Boko Haram.
Chad has also withdrawn its forces.
Nigerian officials told the BBC that almost all of Baga had been set on fire and militants had raided the surrounding area.
Niger Foreign Minister Mohamed Bazoum told the BBC Hausa service: "We have 50 soldiers there and decided to withdraw them after Boko Haram captured Malamfatori town in October and continued to operate in the area with impunity.
"As you know, Baga is under [the control of] Boko Haram terrorists and unless the town is recaptured from them, we will not send back our troops.
"But we are still determined to work with our neighbours Cameroon, Chad and Nigeria to contain the situation - it is a problem for us all."
'Burnt down'
A separate French-led initiative called for all four West African countries to contribute 700 troops each to a multinational force against Boko Haram, but no country has implemented the plan.
Niger has blamed Nigeria, saying it has not kept to commitments regarding its own troop levels.
Civilians who fled from Baga this week reported that they had been unable to bury the dead. Corpses littered the town's streets, said Musa Alhaji Bukar, a senior government official in the area.
