Russia's defence ministry accused Ukraine on Saturday of planning to attack the Kursk nuclear power plant and blamed such a "provocation" on Moscow.
Interfax news agency cited the ministry as saying.
The ministry said Russia would respond harshly in the event of such an attack, which it said would contaminate a large surrounding area.
Ukraine launched an incursion into Russia's western Kursk region on August 6 and has claimed to have taken control of 82 settlements over an area of 1,150 square kilometres (440 square miles) since then.
The Kursk nuclear power plant, however, remains under Russia's control.
At least 15 infants killed in Islamabad hospital fire, local TV reports
US military says it struck vessel in the Caribbean, killing four
Canada announces retaliatory tariffs on $20 billion worth of US goods
Oman, Iran discuss temporary navigation corridor in Strait of Hormuz
Trump administration issues pause on visa appointments for applicants worldwide
