Humanitarian aid for North Korea faces “significant underfunding” while more than half of the country's population faces food insecurity, a new United Nations report said Wednesday.

The report also said that U.S. sanctions forced some U.N. agencies to suspend programs and operations last year.

U.N. humanitarian chief Valerie Amos tweeted the report on the poor, but nuclear-armed country Wednesday.

The report acknowledges the sharp restrictions that North Korea’s government imposes on aid operations, saying the ability of U.N. agencies to freely access communities and obtain consistent data is still “out of reach.” The country has rejected criticism of its bleak human rights record.

The U.N. is seeking $111 million from the international community for operations in the mostly closed-off country in 2015. It is the lowest funding appeal since 2009. It calls the scale of need for the country’s 24 million people “of grave concern.”

The report says the North Korean government has been more open to recognizing its needs, despite being politically sensitive to aid delivery.

The U.S. in 2013 sanctioned North Korea's Foreign Trade Bank, the country's main foreign exchange bank. The restrictions are meant to hurt the country's nuclear weapons and missile programs, which North Korea pursues in defiance of multiple U.N. sanctions.

The U.S. sanctions "led to significant issues and delays in transferring funding into DPRK throughout 2014," the U.N. report says, referring to the country's official name, the Democratic People's Republic of Korea.

That in turn caused "multiple operational obstacles," the report said. In one example, the World Food Program last year cut the number of people it targeted with aid from 2.4 million to 1.8 million.

More than a quarter of children under the age of 5 face chronic malnutrition, the report says.

The U.N. says the sanctions and other factors such as weak infrastructure "all contribute to an unstable economy that could provoke potential humanitarian crises."

The Associated Press contributed to this report.