article_snippet.sent: Release came as Nigerian soldiers backed by warplanes invaded the Islamist's final stronghold in the country - the Sambisa forest - in an effort to finally defeat the six-year-old insurgency.
article_snippet.sent: This morning Nigerian soldiers retreated from Boko Haram last known stronghold in the country amid concerns the Middle East-based militants had booby-trapped the area before fleeing.
article_snippet.sent: Nigerian soldiers have retreated to Bama because of mines.
article_snippet.sent: Nigerian soldiers had been on the road but that made Nigerian soldiers vulnerable, so Nigerian soldiers moved to the bush but there are mines planted there (too),' one soldier, who did not want to be named, revealed.
article_snippet.sent: Chadian military source said a joint military operation involving armies from Niger and Cameroon was expected to begin to encircle the Sambisa forest next week.
article_snippet.sent: Chadians will go in from the Cameroonian border where Chadians have been massing troops.
highlights_snippet.sent: Release comes as Nigerian soldiers stormed the Islamists final remaining stronghold in the country .