"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 in a video message.

"Please support the peace summit with your personal leadership and participation," Zelensky asked, saying that "the efforts of the global majority are the best guarantee that all commitments will be fulfilled".

The conference on the Ukraine war is to be held in Lucerne June 15-16.

The Swiss government has said it has invited 160 delegations but Russia will not attend.

Zelensky said "more than 80 countries confirmed they will come".