UNITED NATIONS: The United Nations has temporarily suspended aid deliveries in Nigeria’s northeastern state of Borno, the former stronghold of Boko Haram, after a humanitarian convoy was attacked, the UN children’s agency UNICEF said on Thursday.

UNICEF said in a statement that unknown assailants attacked the convoy on Thursday as it returned to Maiduguri from delivering aid in Bama, injuring a UNICEF employee and an International Organization for Migration contractor.

“The United Nations has temporarily suspended humanitarian assistance missions pending review of the security situation,” it said.

Nigerian army spokesman Sani Usman said troops were escorting the humanitarian convoy when it was attacked by “suspected remnants of Boko Haram” and that two soldiers and three civilians were wounded.

The convoy was ambushed by the militants on Thursday in Nigeria’s restive northeast, leaving several people wounded.

It was the first such attack on aid workers in the volatile region, the epicenter of the seven-year Boko Haram insurgency in Nigeria’s mainly-Muslim north.

“The convoy was traveling from Bama to Maiduguri in Borno State, Nigeria, returning from delivering desperately needed assistance,” when it was ambushed, UNICEF said in a statement Friday.

“Unknown assailants attacked a humanitarian convoy that included staff from UNICEF, UNFPA, and IOM,” the statement added.

It said a UNICEF employee and an IOM contractor were injured in the attack and were being treated at a local hospital.

“All other UNICEF, IOM and UNFPA staff are safe,” it added.

UNICEF said the team was in a remote area of northeastern Nigeria, where protracted conflict has caused extreme suffering and has triggered a severe malnutrition crisis.

“This was not only an attack on humanitarian workers. It is an attack on the people who most need the assistance and aid that these workers were bringing,” it added.

UNICEF said the UN had temporarily suspended humanitarian assistance missions in the area pending a review of the security situation.

The Nigerian army confirmed the incident in a statement by its spokesman Col. Sani Usman.

“Troops returning from Bama on humanitarian escort duty, were ambushed en route (to) Maiduguri by suspected remnants of Boko Haram terrorists hiding in Meleri village, a few kilometers from Kawuri,” it said.

It said the military repelled the attack, leaving two soldiers and three civilians injured, including UN aid workers.

Some cities in the northeast, including Bama, had gone up to 18 months without any humanitarian deliveries before aid agencies and the UN arrived in June.

Many areas can only be accessed under escort from the Nigerian army. The UN said in May that 9.2 million people living around Lake Chad, which forms the border of Nigeria, Chad, Cameroon and Niger, were in desperate need of food. Seven million of them are in Nigeria.

The medical charity Doctors Without Borders this week also raised the alarm, saying its teams had recently found extremely high levels of malnutrition in northeastern Borno state.

The charity known by its French acronym MSF said the there were between 500,000 and 800,000 people trapped in the area that cannot be reached by humanitarian workers.

Boko Haram, which seeks to impose strict Islamic law in northern Nigeria, has been blamed for some 20,000 deaths and displacing more than 2.6 million people since 2009.

Nigeria’s government has been encouraging people to return home since the recapture of swathes of territory lost to the Islamist militants in 2014 but most are still largely reliant on food handouts.

Nearly a quarter of a million children in Borno suffer from life-threatening malnourishment and around one in five will die if they do not receive treatment, UNICEF said earlier this month.

Medecins Sans Frontieres said on Wednesday that severely malnourished children were dying in large numbers in northeast Nigeria, where food supplies are close to running out.

By 2014, Boko Haram controlled territory nearly the size of Belgium in northeast Nigeria until most of it was recaptured last year by the Nigerian army and troops from neighboring countries.

More than 15,000 people have been killed and at least 2 million displaced by Boko Haram’s insurgency in Nigeria. The group has carried out suicide bombings in northeast Nigeria and neighboring Cameroon, Niger and Chad.