Russia is considering strikes on Ukrainian nuclear power plant substations, Ukraine's Main Directorate of Intelligence (HUR) said Saturday.

"In order to force Ukraine to sign unacceptable surrender demands to end the war, the aggressor state Russia is considering the option of attacking strategic facilities of our state's energy system - we are talking about electricity transmission substations that ensure the operation of Ukrainian nuclear power plants," HUR said in a post on Telegram.

"As part of its pressure campaign, Moscow also plans to intensify intimidation of European countries and the West in general in order to restrain support for Ukraine, in particular our ability to repel Russian terrorist air strikes on critical energy infrastructure facilities," the military intelligence service of Ukraine's Ministry of Defense added.

The report comes as Ukraine's peace negotiators arrived Saturday in the U.S. for talks on the details of a proposed agreement to end the four-year war with Russia.

"Ukraine needs a just peace. We are working to achieve results," Kyrylo Budanov, a former military intelligence chief, said on the Telegram app.