World leaders gathered at a Swiss mountain resort on Saturday to try to build support for Ukraine's peace proposals at a summit skipped by US President Joe Biden, shunned by China and dismissed as a waste of time by Moscow.

More than 90 countries will take part, but China's absence in particular has dimmed hopes the summit would show Russia as globally isolated, while recent military reverses have put Kyiv on the back foot. The war in Gaza between Israel and Hamas has also diverted the world's attention from Ukraine.

The talks will focus on broader concerns triggered by the war, such as food and nuclear security.

Ukrainian President Volodymyr Zelenskiy has trumpeted the summit's wide attendance as a success and predicted "history being made", adding that agreements stemming from it will be part of the peacemaking process.

"Ukraine never wanted this war. It's a criminal and absolutely unprovoked aggression by Russia," he said alongside Swiss President Viola Amherd, who said the conflict had brought "unimaginable suffering" and violated international law.

German Chancellor Olaf Scholz called the gathering an important step to discuss peace and security questions.

"This is a small plant that needs to be watered, but of course also with the perspective that more can then come out of it," he told Welt TV.

Biden sent US Vice President Kamala Harris to represent him—riling Kyiv—while Saudi Arabian Crown Prince Mohammed bin Salman will be represented by his foreign minister and India dispatched a lower-level delegation. Beijing is staying away after Russia was frozen out of proceedings.

Harris announced more than $1.5 billion in energy and humanitarian aid for Ukraine, where infrastructure has been pounded by Russian airstrikes since the 2022 invasion.

"This war remains an utter failure for [Russian President Vladimir] Putin," Harris said during a meeting with Zelenskiy.

A military helicopter hovered over the luxury Buergenstock resort overlooking Lake Lucerne on Saturday as leaders arrived by helicopter on a patch of grassland fenced off with razor wire while cows grazed nearby.

On the eve of the summit, Putin said Russia would end the war only if Kyiv agreed to drop its NATO ambitions and hand over four provinces claimed by Moscow—demands Kyiv swiftly rejected as tantamount to surrender.

Putin's conditions apparently reflected Moscow's growing confidence that its forces have the upper hand in the war. Scholz cast them as an attempt to muddy the waters.

"Everyone knows that this is not a serious proposal, but had something to do with the peace conference in Switzerland," he said in a separate TV interview.

Russian Foreign Ministry spokeswoman Maria Zakharova said Putin's proposal had "shown the real path to peace".

"If you want to save the world, discuss Vladimir Putin's proposal ... Only those who do not want peace can't see, can't understand it," TASS news agency quoted her as saying.

China and Russia

Zelenskiy has accused Beijing of helping Moscow undermine the gathering, an accusation China's Foreign Ministry denied.

The leaders of France, Germany, Italy, Britain, Canada and Japan are among those due to attend. Turkey and Hungary, which maintain friendlier ties with Russia, are also expected to join.

Austrian Chancellor Karl Nehammer said it was an opportunity to start building a broader global consensus to put pressure on Russia.

"It's like we're in a Western echo chamber. That is: all Western European countries, the USA, we agree on what we want to happen with Ukraine," Nehammer said. "But that alone is not enough."

Neutral Switzerland, which took on the summit at Zelenskiy's behest, wants to pave the way for a future peace process that includes Russia. Saudi Arabia or Turkey have been mooted as possible hosts.

Calls for Russia to be at the table will only get stronger over time, said Bob Deen, senior research fellow at the Netherlands-based Clingendael Institute think-tank.

"There is a risk that if Ukraine waits too long, it might end up with rival formats popping up. It may risk losing the initiative," Dean told a forum on the summit's sidelines.

Supporters of Ukraine are marking the talks with a series of events in the nearby city of Lucerne to draw attention to the war's humanitarian costs.

On Saturday afternoon, about 250 people gathered in the centre of the city, many wrapped in Ukrainian flags, wearing traditional clothes and carrying pictures of missing brothers, husbands or sons as they shared their stories.

"I'm clinging to the idea that my husband is still alive," said Svitlana Bilous, the wife of a soldier who has been missing for more than 14 months. "That's what keeps me going."