Nigeria's military has claimed the killing of scores of Boko Haram insurgents and the rescue of 20 hostages during an operation in the notorious Sambisa forest, an Islamist stronghold.

The defence ministry said troops forged ahead in the forest, despite numerous land mines which still litter the area.

In a statement, it added that "scores of the terrorists died in the assault on their bases" yesterday.

"A total of 20 women and children were rescued" in the operation in the northeast of the country, it added.

There was no way to independently verify the military's claims.

One soldier died while ten others were wounded in the assault on rebel bases, according to the statement.

The defence ministry's accounts of clashes with Boko Haram have in the past not been consistent with eye witness reports.

However, Nigeria has reportedly won a series of successes over the insurgents in recent weeks.

More than 700 hostages, primarily women and children, have reportedly been freed during the military's assault on Sambisa, which Boko Haram has used as a base for several years.

According to Amnesty International, the extremists have kidnapped more than 2,000 women and girls since the start of last year.

Many female hostages were victims of sexual violence while in captivity.

Nigeria's latest assault on the insurgents has been backed by troops in neighbouring Chad, Cameroon and Niger.

Despite the apparent successes, attacks have continued, including a surge in violence this week in northeastern Adamawa state, which has been relatively quiet for months.

Experts believe that while Boko Haram has been flushed out of dozens of towns it previously controlled, the group will continue to launch attacks, particularly targeting defenceless civilians.