Ukraine's nuclear agency said on Friday it was recording increased radiation levels from the site of the defunct Chernobyl nuclear power plant.

Experts at the agency did not provide exact radiation levels but said the change was due to the movement of heavy military equipment in the area lifting radioactive dust into the air.

Presidential advisers meanwhile said President Volodymyr Zelenskyy was still in the capital Kyiv.

"The base scenario of Russia's special operation is clear. The sole goal – to take Kyiv and kill Ukraine's authorities," said Mykhailo Podolyak, an adviser to the Ukrainian presidential office, adding that President Zelenskyy is a target.

Russia denied the development, saying that Moscow will deploy paratroopers to help guard the closed Chernobyl nuclear power plant, a spokesperson for Russia's Defense Ministry said on Friday.

Radiation levels at the plant are normal, the spokesperson told a briefing.