<a href="https://www.thenationalnews.com/tags/ukraine" target="_blank">Ukrainian </a>President Volodymyr Zelenskyy expressed disappointment that “some world leaders” had not signed up to a peace summit this month, after <a href="https://www.thenationalnews.com/tags/china" target="_blank">China </a>signalled Xi Jinping would not attend and with US President Joe Biden yet to commit. Mr Zelenskyy made the remarks at a security forum in <a href="https://www.thenationalnews.com/tags/singapore" target="_blank">Singapore </a>as he sought to rally support for the conference on Ukraine taking place in <a href="https://www.thenationalnews.com/tags/switzerland" target="_blank">Switzerland </a>in June. He also appealed for more military aid for Ukraine, which has been ceding ground to Russian troops. “We are disappointed that some world leaders have not yet confirmed their participation in the peace summit,” Mr Zelenskyy said at the Shangri-La Dialogue, without mentioning China or the US by name. The peace summit threatens to be overshadowed if key Ukraine backer Mr Biden – who is locked in campaigning against Donald Trump and has given no sign he would participate – ultimately stays away. He accused China of working hard to stop countries from attending the summit, which Beijing has criticised because Russia is not invited. “China, unfortunately, is working hard today to prevent countries from coming to the peace summit,” Mr Zelenskyy told reporters during the Shangri-La Dialogue, which draws defence officials from around the world. Beijing believes the conference “should have the recognition of Russia and Ukraine, equal participation of all parties and fair discussion of all peace plans”, Foreign Ministry spokeswoman Mao Ning said on Friday. “Otherwise, it is difficult for the conference to play a substantive role in restoring peace,” she said. Mr Zelenskyy also met US Defence Secretary Lloyd Austin on Sunday on the sidelines of the Singapore security forum. Mr Zelenskyy told reporters they had a “very good” meeting. In a post on X, Mr Zelenskyy said the pair discussed “the defence needs of our country, bolstering Ukraine's air defence system, the F-16 coalition, and drafting of a bilateral security agreement”. In a readout of the talks, Pentagon spokesman Maj Gen Pat Ryder said Mr Austin reiterated “unwavering US support for Ukraine in the face of Russian aggression”. Mr Austin also “reaffirmed the US commitment to maintaining the strong support of a coalition of over fifty countries to help Ukraine defend its freedom”, Maj Gen Ryder said. The meeting came after Washington decided to partially lift restrictions on using US-provided weapons to strike inside Russia, which Mr Zelenskyy has hailed as a “step forward”. Mr Zelenskyy and Mr Austin last met face-to-face in December in Washington, where Mr Zelenskyy made a last-ditch plea for US aid before it ran out. The US Congress approved in April a $61-billion aid package for Ukraine following months of political wrangling, unlocking much-needed arms for the country's outgunned troops. Chinese defence spokesman Wu Qian told AFP he was not aware of any plans for Chinese Defence Minister Dong Jun to meet Mr Zelenskyy in Singapore. Ukraine is struggling to hold back a Russian ground offensive in the Kharkiv region, where Moscow recently made its largest territorial gains in 18 months. Mr Zelenskyy has been touring European nations in recent days seeking more military aid for Ukrainian troops, and warning partners of the risks if they show any signs of fatigue over the war. “It is very important for Ukrainians that the world does not get tired … that the world understands that it cannot get tired of the war launched by the aggressor,” Mr Zelenskyy said in Portugal on Tuesday. <i>Agencies contributed to this report.</i>