The alleged kidnapping took place just days after 30 troops vanished following a raid on a military base in the same region amid a surge in bloody violence.
Sources told AFP the loggers, mostly in their twenties, had left the town of Gamboru on the border with Cameroon Tuesday morning to fetch firewood in a Boko Haram hotspot.
“All 31 have not been seen since yesterday and it is obvious they were seized by Boko Haram,” said Umar Kachalla, a militia in Gamboru fighting Boko Haram alongside the military.
The loggers had left for Wulgo village in nearby Marte district, 15 kilometres away, with their axes and wooden carts to collect wood to sell and raise money to buy food, Kachalla said.
Two weeks ago, Boko Haram gunmen shot dead 10 loggers from Gamboru in the bush outside Wulgo while collecting firewood, said another militia Shehu Mada.
“We believe Boko Haram abducted them to use them as fighters, given their young age,” Mada said. “They (Boko Haram) abandon the bodies of their victims when they kill them but the fact that the bodies of the loggers have not been seen is clear indication they were abducted,” said Mada.
Boko Haram fighters still operate in hard-to-reach rural areas where military operations are minimal. In August 2014, the group seized Gamboru, a trading hub along with the neighbouring town of Ngala. Nigerian troops retook both towns in September 2015 with the help of Chadian forces following offensives lasting months.