The UN on Monday said it needed roughly $160 million for Nigeria's conflict-battered northeast, where the situation is at its worst in five years, according to the local head of the body's humanitarian arm.

The region has been plagued by a 15-year jihadist insurgency that has killed more than 40,000 people and displaced over two million. The fighting has also ruined livelihoods and hindered access to agricultural land and markets. 

The funds are needed to provide nutritional and health supplies to two million people, including 600,000 children in the Borno, Adamawa and Yobe states, officials said. 

The request comes as cuts by the United States have hampered the humanitarian response in the region.

Speaking to reporters, officials from the World Food Programme, Food and Agriculture Organization and children's fund UNICEF warned that the already precarious humanitarian situation could be worsened by a disease outbreak or natural disaster such as flooding, which the region would not be prepared for.

"This is urgent," said Trond Jensen, who heads the Nigeria office of the UN's humanitarian response arm, UNOCHA. "We need the support now, not next week, not next month."

"I cannot say how desperate the situation is," he added. "It's the worst that I've seen in five years."

Jensen said cuts by the United States, notably to its main foreign development arm USAID, have had a critical impact on the capacity to provide critical services to people in the region. 

"If these children don't get access to those treatment services they will die," said Nemat Hajeebhoy, nutrition chief at UNICEF Nigeria.