Ukraine's President Volodymyr Zelenskyy said the whole world, including his country, wants Russia to take part in a second peace summit planned for this year, changing his stance after Kyiv excluded Moscow from the first talks.

"The majority of the world today says that Russia must be represented at the second summit, otherwise we will not achieve meaningful results," Zelenskyy said.

"Since the whole world wants them to be at the table, we cannot be against it," he told AFP and other French media during an interview Tuesday in western Ukraine.

Russian President Vladimir Putin has said he is open to negotiations, but he would only order a cease-fire if Kyiv effectively surrendered territory that Moscow claims as its own.

Zelenskyy also said he did not want China, which recently hosted Ukraine's foreign minister for talks and is a close ally to Moscow, to mediate peace efforts. He urged urged Beijing to pressure Moscow into ending the war.

"If China wants, it can force Russia to stop this war. China is an integral part of this world and an influential state," he said.

"I would like them not to be in a mediating role. I would like them to put pressure on Russia," the Ukrainian leader added.

In the wide-ranging interview, Zelenskyy also said Russian forces had made gains in eastern Ukraine because Kyiv's allies are restricting its use of Western-supplied weapons and its forces are still awaiting arms deliveries from abroad.

"It's a serious challenge that we can't use all the weapons we need to stop this enemy," he said, adding that Ukraine was awaiting fresh weapons to equip reserve brigades.

"If you use the weapons of our partners, then they can say that we won't give you any more help, that's the risk," he said.

Zelenskyy said Kyiv was "working very hard" to get permission to strike targets deep inside Russian territory with Western-supplied weapons.

"Unfortunately, our partners are still afraid of this," he added.

"We no longer keep it a secret that we were preparing 14 brigades. Do you think it is possible to stop them if only three out of 14 are equipped?" he added, explaining how Russia had been able to capture a string of villages in the eastern Donetsk region over recent months.

Zelenskyy also said the upcoming presidential election in the United States, a vital military and political ally for Ukraine, poses a "challenge" for Kyiv.

"We cannot influence any election. Of course, the United States is a challenge today. And there are risks that probably none of us can predict," he told reporters.