Nigeria's military on Wednesday said troops had rescued 241 women and children during operations against Boko Haram Islamist militants in the country's restive northeast.

The women and children were picked up on Tuesday as soldiers cleared what the military said were "terrorist camps" near Banki in Borno state, close to the border with Cameroon.

Boko Haram has used Banki to launch cross-border attacks, including in and around the Cameroon town of Amchide, where the Islamists clashed with security forces and there were failed suicide attacks Tuesday.

Army spokesman Sani Usman told AFP separately it was not immediately clear whether all of those rescued had been kidnapped by the Islamists.

"Screening is ongoing to know their exact status. Some were being held, some belonged to their (the militants') families," he said.

Amnesty International said earlier this year that Boko Haram had seized more than 2,000 women and girls since January 2014, as part of their quest to establish a hardline Islamic state in the region.

Several hundred women and children were brought out of the group's Sambisa Forest stronghold in Borno state in May, while last month nearly 180 were freed south of the state capital, Maiduguri.

Usman said 43 suspected Boko Haram fighters were detained in Tuesday's operations in Jangurori and Bulatori villages, including a suspected regional commander or "emir".

There was no independent verification of the army's claims, which come after a series of apparent successes against the Islamists.

Usman claimed the rebels were in a "serious state of disarray". Boko Haram's leader Abubakar Shekau last weekend dismissed the military's assertion the group was a spent force as "lies".

The rebels' ability to hit "soft" civilian targets appears undiminished, however, and a series of bomb attacks in Maiduguri and Monguno, in northern Borno, on Sunday, killed nearly 140.