Nigeria's president says his country's military will only use the minimum force necessary to deal with extremists after calls for an investigation into senior commanders over abuses, including the deaths of more than 8,000 detainees.

President Muhammadu Buhari told European Union lawmakers Wednesday that Nigeria's military has updated its "rules of engagement in fighting terrorism" and that care is being taken in "the treatment of captured terrorists."

He said attention would be paid to civilians caught up in any fighting and protecting property.

Amnesty International demanded last year an investigation into nine commanders, including Maj. Gen. Ahmadu Mohammed, over possible war crimes including more than 8,000 detainee deaths since 2011.

Buhari promised a probe and to deal with any abuses by the military, but nothing has been done.