Boko Haram Islamists kidnapped scores of people from fishing communities in the northeast of Nigeria, hauling some of the hostages away on boats across Lake Chad, witnesses said.
Several people were also reportedly killed in the militant raids on a number of villages in the Kukawa Local Government area in Borno state, a Boko Haram stronghold.
The kidnappings took place on Sunday, but due to poor mobile phone coverage in the remote details of the attacks took days to emerge.
A few survivors travelled to Borno's capital Maiduguri, where they told reporters about the latest mass abduction by the insurgents, who are accused of killing more than 10,000 people since 2009.
"At first we thought (the attackers) were soldiers... But when they began shooting at people and setting fire to homes we realised they were Boko Haram," one witness said.
She said the militants kidnapped roughly 100 men and boys aged between 15 and 30 as well as several women and girls.
The kidnappings come four months after Boko Haram, which is fighting to reinstate a medieval Islamic caliphate in religiously mixed Nigeria, abducted more than 200 schoolgirls from the village of Chibok.
They are still missing.
Another woman who escaped Sunday's raid said locals feared the hostages would be used as "foot soldiers" by Boko Haram, who regularly carry out strikes on military and civilian targets in the impoverished area.
The once-grassroots movement has rapidly lost popular support as it gets more bloodthirsty.
Its solution - kidnapping boys and forcing them to fight and abducting girls as sex slaves - is a chilling echo of Ugandan rebel Joseph Kony's Lord's Resistance Army, which has operated in the same way in Uganda, South Sudan and central Africa for decades
A multi-national force made up of troops from Nigeria, Chad and Niger are nominally responsible for security in the area.
The force was formed more than a decade ago - long before Boko Haram became a threat - to crack down on cross-border smuggling.
The survivors who spoke to reporters said soldiers from this force were deployed to the area after the attacks and clashed with Boko Haram fighters on Wednesday when the insurgents returned.
The military did not respond to a request for comment. A security source said they were aware of the incident but were still investigating the details.
The kidnappers overpowered local vigilantes who had no support because this is no military presence there, the villagers said.