Ukrainian President Volodymyr Zelensky has accused Russia and China of attempting to undermine his upcoming global peace summit in Switzerland.
He said Russia was trying to dissuade other states from attending the event, and that China was working to do this as well.
Speaking at an Asian security forum, he also said there were “elements of Russia’s weaponry” that come from China.
China says it does not side with either side of the Ukraine war, a position that has been increasingly questioned particularly by the US.
Beijing is accused of aiding Moscow by sending components for weapons. It is also seen as propping up the Russian economy by purchasing vast quantities of oil and gas, softening the impact of Western sanctions.
Mr Zelensky made a surprise appearance at the Shangri-la Dialogue in Singapore attended by defence chiefs from around the world, including US Secretary of Defense Lloyd Austin and Chinese defence minister Dong Jun.
The visit was aimed at drumming up support from Asian countries. Besides meeting regional leaders, he also urged delegates to attend his summit due to be held later in June.
Mr Zelensky said it would focus on achieving nuclear security, food security, and the release of prisoners of war and Ukrainian children held in Russia.
So far 106 countries said they would send high-level representatives or their leaders to the summit, he said.
Russia has not been invited and China is not attending.
A formal invitation was not issued to Russia as Moscow had told Switzerland early on that it did not want to participate, the BBC understands.
Mr Zelensky claimed that Russia was attempting to disrupt the summit by pressuring countries not to attend, through threats of a blockade of agricultural goods, chemical goods, and energy.
Certain countries were assisting this “diplomatic disruption”, he added.
He named China later on, and said it was “working for countries to not come to the peace summit”, unlike the US which has promised to send a high-level representative and is encouraging others to attend.
China's foreign ministry had said that the conference "should have the recognition of Russia and Ukraine" and equal participation. "Otherwise, it is difficult for the conference to play a substantive role in restoring peace," a spokeswoman said on Friday.
Mr Zelensky also said China's leader Xi Jinping had earlier promised him they would “stand aside in this war and would not support Russia with weapons”.
But, he added, there are now “elements that are part of Russia’s weaponry” that come from China, according to various intelligence agencies. He called for China to maintain a “consistent” position.
The US has said that China is helping Russia make more munitions, armoured vehicles and missiles. It estimates about 70% of the machine tools and 90% of the microelectronics Russia imports come from China.
Earlier on Sunday, Chinese defence minister Dong Jun said they do not supply weapons to either party of the Ukraine conflict.
He also said they have put "strict controls" on the exports of dual-use technology, which are items that can be used for civilian and military purposes.
"We have never done anything to fan the flames. We stand firmly on the side of peace and dialogue," he said in his speech.
Mr Zelensky said he did not meet Mr Dong at the dialogue, but he did meet Mr Austin. The two discussed the US’ decision to let Ukraine use American weapons on Russian territory, according to Mr Zelensky.
That decision comes with certain restrictions. Asked by the BBC if he requested the removal of limitations, he said he was grateful to the US for allowing Ukraine to use the HIMARS artillery rocket system by the border of the Kharkiv region which has seen intense fighting.
“Is that sufficient? No,” he said, adding that there were airfields from which Russia was permanently firing “knowing that Ukraine will not fire back”.
The US joins other Western states such as France in allowing Ukraine more leeway in using Western-supplied weapons. Russia has warned of “serious consequences” of this move.
This weekend marked the second time Mr Zelensky has visited Asia since the war began. He made a surprise appearance at the G7 leaders’ summit a year ago in Hiroshima, Japan.