Ukrainian President Volodymyr Zelensky on Sunday urged US President Joe Biden and China's President Xi Jinping to attend a peace summit in Switzerland next month.

The Ukrainian leader made the request in English in an emotive video showing him standing in front of ruins in the heavily bombarded eastern city of Kharkiv.

"I am appealing to the leaders of the world who are still aside from the global efforts of the global peace summit: to President Biden, the leader of the United States, and to President Xi, the leader of China," Zelensky said.

"Please support the peace summit with your personal leadership and participation," he asked.

Zelensky said that the leaders should attend because "the efforts of the global majority are the best guarantee that all commitments will be fulfilled".

He also said he wanted the attendance of leaders "whom Russia will not be able to deceive".

The conference on the Ukraine war is to be held at a luxury resort near Lucerne from June 15-16.

The Swiss government is hosting the event at Ukraine's request.

It has said it has invited 160 delegations but Russia will not attend the event, which is expected to last just over a day.

Biden's presence has not been confirmed, while organisers say countries participating include members of the G7, the G20 and the BRICS group.

Russian President Vladimir Putin said earlier this month "they are not inviting us", adding that Russia would not push to attend an event where it is unwelcome.

China restated its position this week, saying in a joint statement with Brazil that it supports "an international peace conference held at a proper time that is recognised by both Russia and Ukraine, with equal participation of all parties as well as fair discussion of all peace plans".

Xi is Putin's strategic ally, and the Russian leader made a trip to China after re-election this month.

US officials said last month that Beijing is helping Russia with military expansion, including joint production of drones, while stopping short of directly providing weapons to Russia for use in Ukraine.

Zelensky said "more than 80 countries confirmed they will come" to the summit and Ukraine was continuing efforts to invite leaders.