KYIV/WASHINGTON (Reuters) - Ukraine's President Volodymyr Zelenskiy on Sunday warned of more potential Russian attacks on his country's energy infrastructure, as officials urged residents in the capital Kyiv to consider making plans to leave as ongoing strikes threaten the power supply.
Zelenskiy, in his regular nightly address, said Russia was "concentrating forces and means for a possible repetition of mass attacks on our infrastructure. First of all, energy."
More than 4.5 million consumers were already without power, Zelenskiy said, amid concerns support for Ukraine's cause could waver as the war's impacts of energy and food prices persist into winter.
U.S. National Security Advisor Jake Sullivan, who travelled to Kyiv on Friday and pledged Washington's "unwavering and unflinching" support for Ukraine, has held undisclosed talks with Russian officials designed to avoid further escalation, the Wall Street Journal reported on Sunday.
News of those contacts emerged after a report said Washington was urging Kyiv to signal an openness to talks with Russia.
Presidential adviser Mykhailo Podolyak said earlier on Twitter that Ukraine would "stand" despite Russian attacks on its energy infrastructure, adding that this would be done by using air defence, protecting infrastructure and optimising consumption.
The country faced a 32 percent deficit in projected power supply Monday, Sergei Kovalenko, CEO of YASNO, a major supplier of energy to the capital, said on his Facebook page.
The warnings followed remarks by Kyiv Mayor Vitali Klitschko urging residents to "consider everything" including a worst-case scenario where the capital loses power and water.
Residents should consider staying with friends or family outside the city, he said in a television interview.
In the south, Russia and Ukraine continued to trade allegations as a Ukrainian advance continues on the southern city of Kherson. Reuters was unable to immediately verify battlefield accounts from either side.
Yaroslav Yanushevych, governor of Kherson region, said Russian forces destroyed about 1.5km of power lines, cutting the power supply to the city of Beryslav.
"It is likely that there will be no electricity in Beryslav until it is fully freed from occupation," Yanushevych wrote on the Telegram messaging app, adding that power lines leading to Kherson had also been destroyed.
Russian news agencies reported on Sunday that Ukraine's vast Russian-held Nova Kakhovka dam, upstream of Kherson on the Dnipro river, was damaged in shelling by Ukrainian forces. The reports provided no evidence to support the allegation, which could not be immediately verified by Reuters.
Russian state-owned TASS quoted an emergency services representative as saying that a rocket launched by a U.S.-made HIMARS missile system had hit the dam's lock and caused damaged. The official quoted said it was an "attempt to create the conditions for a humanitarian catastrophe" by breaching the dam.
The warnings came as the Wall Street Journal reported that the White House's Sullivan held confidential conversations in recent months with Kremlin aide Yuri Ushakov and Russian Security Council secretary Nikolai Patrushev that were not disclosed publicly.
Few high-level contacts between U.S. and Russian officials have been made public in recent months as Washington has insisted that any talks on ending the war in Ukraine be held between Moscow and Kyiv.
The White House declined to comment on the report, responding to questions about the story only with a statement attributed to National Security Council spokesperson Adrienne Watson: "People claim a lot of things."
On Saturday, the Washington Post reported that the Biden administration is privately encouraging Ukraine to signal an openness to negotiate with Russia, the Washington Post reported, as the State Department said Moscow was escalating the war and did not seriously wish to engage in peace talks.
The newspaper cited unnamed sources as saying the request by American officials was not aimed at pushing Ukraine to the negotiating table, but a calculated attempt to ensure Kyiv maintains the support of other nations.
U.S. and Ukrainian officials acknowledged that Ukrainian President Volodymyr Zelenskiy's ban on talks with Russian President Vladimir Putin had generated concern in parts of Europe, Africa and Latin America, where the war's effects on costs of food and fuel are felt most sharply, the Post said.
"Ukraine fatigue is a real thing for some of our partners," it quoted an unnamed U.S. official as saying.
Zelenskiy signed a decree on Oct. 4 formally declaring the prospect of any Ukrainian talks with Putin "impossible" but leaving the door open to talks with Russia.
The White House National Security Council had no immediate comment on the accuracy of the report.
A State Department spokesperson responded: "We've said it before and will say it again: Actions speak louder than words. If Russia is ready for negotiation, it should stop its bombs and missiles and withdraw its forces from Ukraine."
(Reporting by Reuters bureaux; Writing by Michael Perry and Simon Lewis; Editing by William Mallard, William Maclean and Diane Craft)