The World Food Program says South Sudan's government has suspended airdrops of food aid, the latest obstacle humanitarian officials have faced in this troubled country.

WFP spokesman Challiss McDonough says the latest halt of airdrops is due to a "misunderstanding regarding flight clearances" and says the issue is likely temporary.

South Sudan faces one of the world's worst humanitarian crises. Civil war that began in 2013 made widespread hunger problems worse. The government says food prices in some areas are 10 times higher than a year ago.

South Sudan has been criticized for blocking aid delivery amid some officials' hostility at the international community. Officials have said restrictions are necessary for security.

When the U.N. Security Council visited the country in September, the government pledged to "immediately improve humanitarian access."