The US is privately encouraging Ukraine to signal an openness to negotiate with Russia, the Washington Post has reported.
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.
US and Ukrainian officials acknowledged that Ukrainian President Volodymyr Zelenskyy’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 US official as saying.
Mr Zelenskyy signed a decree on October 4 formally declaring the prospect of any Ukrainian talks with Mr 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 representative said: “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.
“The Kremlin continues to escalate this war. The Kremlin has demonstrated its unwillingness to seriously engage in negotiations since even before it launched its full-scale invasion of Ukraine.”
The official also noted remarks by Mr Zelenskyy on Friday, in which he said: “We are ready for peace, for a fair and just peace, the formula of which we have voiced many times.”
In his nightly address to the Ukrainian people on Friday, Mr Zelenskyy said: “The world knows our position. This is respect for the UN Charter, respect for our territorial integrity, respect for our people.”
US National Security adviser Jake Sullivan said during a visit to Kyiv on Friday that Washington's support for Ukraine would remain “unwavering and unflinching” after Tuesday's midterm congressional elections.
The US announced $400 million worth of additional security assistance for Ukraine, including refurbishing T-72 tanks from the Czech Republic and missiles for Hawk air defences that could be used against Russian drones and cruise missiles.
The new assistance brought the amount of US military aid sent to Kyiv to more than $18.2 billion since the invasion.
Citing emergency services, Russian news agencies reported on Sunday that Ukraine's vast Russian-held Nova Kakhovka dam 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 news agency Tass quoted a representative of the emergency services as saying that a rocket launched by a US-made Himars missile system had hit the dam's lock and caused damage. The official said it was an “attempt to create the conditions for a humanitarian catastrophe” by breaching the dam.
The dam, which blocks the Dnipro river upstream of the southern city of Kherson where Ukrainian forces have been making advances, has taken on strategic significance in recent weeks.
Since October, both Russia and Ukraine have repeatedly accused each of planning to breach the dam using explosives, in a move that would flood much of the area downstream and would be likely to cause major destruction around Kherson city.
In the latest sign of Russia's retreat in one of the most bitterly contested areas, Mr Putin publicly endorsed the evacuation of civilians from parts of the Kherson region on Friday.
This appeared to be the first time Mr Putin has endorsed the evacuations personally, although Moscow has been ferrying people out of an area it controls in Kherson on the west bank of the Dnipro River.
Last week Russia said the evacuation zone would also include a 15-kilometre buffer area on the east bank.
Kyiv says the measures have included forced deportations of civilians, a war crime, which Russia denies.
Mr Putin's comments came amid signs Russia could be preparing to abandon its military foothold on the west bank of the Dnipro, including Russian-held Kherson city.