The United Nations' nuclear watchdog, the International Atomic Energy Agency, declared Wednesday that some 2.5 tons of natural uranium have gone missing from a site in Libya.

IAEA chief Rafael Grossi told the UN agency's member states that inspectors on Tuesday found that 10 drums containing uranium ore concentrate had up and disappeared, saying they "were not present as previously declared" at the location in Libya.

According to Grossi, the IAEA will conduct further activities "to clarify the circumstances of the removal of the nuclear material and its current location", though the agency's top executive did not provide further details regarding the site.

Natural uranium cannot immediately be used for energy production or nuclear warheads, as the enrichment process typically requires the metal to be converted into a gas, then later spun in centrifuges to reach the levels needed.

However, each ton of natural uranium can be refined with adequate technological means and resources into 5.6 kilograms of weapons-grade material over time, making finding the missing uranium of utmost importance for nonproliferation experts.

Check out: Natural Resources in Libya

Libya had abandoned in 2003 a program to develop nuclear weapons under assassinated former President Muammar Gaddafi.

Since the 2011 West-led war on Libya, the country has been split between the two parties after its leader was killed after NATO-led aggression on the country that engulfed it in civil war.

After the NATO-backed insurgency in Libya that was accompanied by direct hostile intervention by the alliance, Libya has been a battlefield for global powers, which led to different regions of the country falling under the control of various factions and militants due to the lack of any stable and central governance of the war-torn country.

Reuters a first reported on the IAEA warning about the missing Libyan uranium, saying the IAEA told members reaching the site that’s not under government control required "complex logistics."

The IAEA declined to offer more details on the missing uranium.

One such declared site is Sabha, some 660 kilometers (410 miles) southeast of Libya's capital, Tripoli, in the country's Sahara Desert, with estimates putting the Libyan stockpile at some 1,000 metric tons of yellowcake uranium.

Former President Muammar Gaddafi declared Libya's nuclear weapons program to the world in 2003, as he rescinded the country's bid to create nuclear weapons.