Nigeria’s army is investigating alleged misconduct by soldiers providing security at a camp for people who fled an Islamist insurgency, a military spokesman said on Tuesday.

Boko Haram militants have displaced more than two million people in northeastern Nigeria since 2009 and over 20,000 people have been killed in that time. Tens of thousands live in camps for displaced people guarded by government troops.

Army spokesman Sani Usman said the military had “noted with great concern growing allegations of misconduct” by soldiers on security duty at a camp in Bama, a town in Borno state.

He said the allegations, which he did not describe in detail, were so far unsubstantiated but the chief of army staff, Lieutenant General Tukur Yusufu Buratai, had ordered an investigation.

Usman said Nigeria had no tolerance for abuses by army officers and soldiers, and anyone found culpable would be

“severely dealt with”.

It is not the first time allegations of abuse by soldiers guarding refugee camps from Boko Haram have surfaced.

Last year Human Rights Watch said it had uncovered 43 cases of sexual abuse, including rape and exploitation, by security officers at camps in the northeast.

Boko Haram held a swathe of territory in the northeast around the size of Belgium as of early 2015 but has since been pushed out of most of it by Nigerian troops backed by soldiers from neighbouring countries.

The jihadists continue to carry out suicide bomb attacks and armed raids in northeastern Nigeria as well as in neighbouring Cameroon and Niger.