Troops have freed 900 hostages captured by the Nigerian Islamist militant group Boko Haram, Cameroon's defence minister has announced.

Joseph Beti Assomo said his forces had also killed around 100 Boko Haram members at the end of November.

There has been no independent confirmation of the operation in Cameroon's remote Far North region.

It is not clear exactly where the clashes took place, or where Boko Haram's captives had been held.

The statement on public radio on Wednesday said a large stock of arms and munitions had been seized, as well as black-and-white Islamic State flags.

It did not give any details on the identities of the freed hostages.

So it is not known whether those freed include any of the 219 schoolgirls taken from their dormitories in Chibok, Nigeria last year.

At least 17,000 people have been killed and 2,000 abducted since Boko Haram launched its insurgency in 2009, according to Amnesty International.

Until officials in Cameroon provide more details on the hundreds of hostages they claim were freed during a three-day military operation, questions will inevitably remain.

They have yet to say exactly where the operation took place, although reports suggest it was in northern district close to the Nigerian border.

In the past, this sparsely-populated region was used by the insurgents to stockpile weapons and to launch attacks.

But since the start of this year, Boko Haram has been hit hard by military campaigns carried out on both sides of the border.

The areas where they can operate freely in Nigeria and Cameroon are being severely squeezed.

In Nigeria, the military has retaken towns once controlled by the militants.

But that does not mean the insurgents are defeated. Boko Haram has now switched tactics, frequently carrying out suicide attack to deadly effect.

Cameroon has been increasingly drawn into the conflict as there have been regular attacks over recent weeks in the Far North of the country near the border with Nigeria's Borno State, where Boko Haram was founded.

On Tuesday at least three people were killed when two suicide bombers attacked in the region.

Cameroon along with Nigeria, Chad, Niger and Benin have formed a regional force which this year has retaken most territory Boko Haram had seized in north-eastern Nigeria.