A U.N. nuclear team will visit Libya this month to assess the safety of thousands of barrels of milled uranium – known as yellowcake – amid concerns about the country’s deteriorating security situation, a U.N. official said on Monday.

“With respect to yellowcake, we have received information indicating that 6,400 barrels are stored in a non-functional former military facility close to Sabha in the south,” U.N. Libya envoy Tarek Mitri told the Security Council.

“They are under control of a Libyan army battalion,” Mitri told the 15-nation council. An inspection team from the International Atomic Energy Agency will visit this month to verify the stockpiles and storage conditions, he said.