The U.S. Air Force has dispatched a specially designed "nuclear sniffer" aircraft to Europe to monitor heightened levels of radiation originating from an undetermined source.

Unusually high levels of Iodine-131, a manmade radioactive material, reportedly have been detected across the European continent since early January, according to France's Radioprotection and Nuclear Safety Institute (IRSN), which said that the radioactive cloud has since traveled from Norway to Spain. Finland, Poland, the Czech Republic, Germany and France also were affected. In response to the incident, the U.S. sent the WC-135 Constant Phoenix, sometimes called a "nuclear sniffer," which reportedly has landed at Surrey airbase in the U.K.

The aircraft, tasked with isolating the source of the radiation, was "on a preplanned rotational deployment scheduled far in advance," a U.S. Air Force spokesperson told the Independent Thursday. "Anything contrary is completely baseless."

"The WC-135 routinely conducts worldwide missions and we are not going to get into further details." 

The radioactive material was first discovered in the isolated Artic Circle region north of Norway; however, its origins have yet to be determined. The IRSN said the substance's short half-life was "proof of a recent release" and, despite unfounded rumors of a Russian atomic bomb test, established the "most likely source of detected iodine" was "a plant for the production of radioactive elements for medical use," IRSN said in a tweet posted Monday. Iodine-131 has various pharmaceutical uses.

The IRSN also said no other nuclear materials had been discovered, and no health concerns were associated with the levels currently detected. It said it had brought its findings to the Ring of Five, an international group of European organizations dedicated to radiological study. Some have criticized European governments for not making their early January findings public until days ago.

The WC-135 Constant Phoenix has been used to detect radiation levels after nuclear disasters such as the Soviet Union's Chernobyl incident in 1986 and Japan's Fukushima meltdown in 2011. The aircraft also reportedly was dispatched to monitor North Korea's nuclear activity.