South Sudan’s government has indicated that aircraft manufactured 20 years and older will not be allowed to fly in the country, according to a report from the World Food Program.

The order “would have an impact on WFP, UNHAS, and Logistics Cluster fleets,” WFP said. “All aircraft contracted by WFP undergo rigorous safety checks and follow United Nations Aviation Safety Standards,”

Recently, WFP has faced a number of logistical constraints in the country, ranging from trucks stopped at the border of Uganda to flight clearances being delayed. In August, flights from Ethiopia were temporarily banned from entering the country because of additional security constraints.

Government officials have not spoken specifically about the constraint on airplanes manufactured more than 20 years ago, bt have said that the additional constraints are to ensure safety.

Roughly five million people are facing food insecurity in South Sudan, according to UN agencies.