UN watchdog opens investigation after Ukraine said Russian troops at Chernobyl got sick from high radiation levels

• Russian troops gave up control of the Chernobyl nuclear power plant on Thursday, Ukraine said.
• They were exposed to "significant doses" of radiation and started developing symptoms, Ukraine said.

The United Nations atomic watchdog said it is investigating after Ukraine said Russian soldiers at Chernobyl were exposed to high radiation levels and left sick.

The International Atomic Energy Agency said Thursday evening that Russian troops had transferred control of the plant to Ukrainian personnel and moved two convoys of service members toward Belarus.

This was confirmed by Yevhen Kramarenko, the head of Ukraine's agency in charge of the exclusion zone, The Guardian reported.

The Russians seized the power plant on February 24, the first day of the invasion.

The troops had entered the most contaminated part of the Chernobyl exclusion zone — the Red Forest — without any protective gear and exposed themselves to radioactive dust.

Energoatom, Ukraine's state power company, said the soldiers received "significant doses" of radiation after digging trenches in the Red Forest and that they "panicked at the first sign of illness," The Guardian reported.

The symptoms "showed up very quickly," Energoatom said, The Guardian reported.

Reuters reported that Energoatom said "almost a riot began to brew among the soldiers" amid fears over the radiation exposure and suggested that was why they left the zone.

The IAEA said it was investigating the reports of the exposure and would send experts to the plant in the coming days.

The Red Forest surrounds the decommissioned Chernobyl nuclear power plant, which was the site of the world's worst nuclear disaster in 1986. The forest is still the most contaminated area of the zone, Reuters reported.

Two Ukrainian workers who were working at the plant told Reuters earlier this week that the troops had kicked up clouds of radioactive dust while driving through the forest. They also said that some of the Russian soldiers had no idea they were in a radiation zone.

The power plant was fully decommissioned after the 1986 nuclear accident and the remaining work at the site is mostly directed toward decontamination.