Ukraine is preparing to present a revised peace plan to the White House, as it seeks to avoid making territorial concessions to Russia.

Kyiv is set propose alternatives to the US after President Volodymyr Zelensky again ruled out surrendering land, saying he had no right to do so under Ukrainian or international law.

He made the comments as he met European and Nato leaders on Monday, part of a collective push to deter the US from backing a peace deal which includes major concessions for Ukraine, and which allies fear would leave it vulnerable to a future invasion.

Meanwhile, the city of Sumy in north-western Ukraine was left without power overnight after a Russian drone attack. The region's governor said more than a dozen drones had hit power infrastructure, the latest in Russia's nightly attacks. No deaths were reported.

Zelensky's ongoing diplomatic tour of Europe comes after days of intensive talks between US and Ukrainian negotiators that failed to produce a deal Kyiv could agree to. He told a news conference that his team could send a new proposal to the Americans as soon as Tuesday.

On the subject of surrendering land, Zelensky stated: Russia is insisting that we give up territories, but we don't want to cede anything. We have no legal right to do so, under Ukrainian law, our constitution and international law. And we don't have any moral right either.

Zelensky has long maintained that any changes to Ukraine's borders would need to be authorized by a public referendum.

In recent developments, Zelensky noted that the initial 28-point plan proposed by the US had been cut down to 20 points without removing any supportive elements for Ukraine, although no compromises were made regarding territory.

The original US-backed plan had controversially suggested Ukraine hand over total control of the Donbas region, which Russia has not fully captured after years of conflict.

While Zelensky highlights the need for robust security protocols, the exact nature of future guarantees remains unclear as international discussions continue.