Trump reacts as Putin, Kim Jong Un and Xi appear together at China's military parade

President Donald Trump took to his social media platform as Chinese President Xi Jinping, North Korean leader Kim Jong Un and Russian President Vladimir Putin appeared together in Beijing for China's largest-ever military parade on Wednesday.

Trump accused Xi of "conspiring against" the United States as they attended the parade, which marked the 80th anniversary of Japan's surrender in World War II.

"May President Xi and the wonderful people of China have a great and lasting day of celebration. Please give my warmest regards to Vladimir Putin, and Kim Jong Un, as you conspire against The United States of America," Trump wrote on social media as the parade was underway.

Trump referenced America's involvement in World War II in his post on, saying, "The big question to be answered is whether or not President Xi of China will mention the massive amount of support and 'blood' that The United States of America gave to China in order to help it to secure its FREEDOM from a very unfriendly foreign invader."

"Many Americans died in China's quest for Victory and Glory. I hope that they are rightfully Honored and Remembered for their Bravery and Sacrifice!" the president wrote.

In his remarks at the parade, held in front of the Tiananmen Gate, Xi hailed the Chinese People's Liberation Army as a "heroic force" and spoke of nations and treating each other as equals.

“The Chinese nation is a great nation that does not fear violence, and that stands independent and strong," Xi said. "In the past, when confronted with a life-or-death struggle between justice and evil, light and darkness, progress and reaction, the Chinese people stood united, rose up in resistance, and fought for the survival of the country, the rejuvenation of the nation and the cause of human justice."

Yuri Ushakov, a top aide to Putin, dismissed Trump's conspiracy allegations.

"I want to say that no one organized any conspiracies, no one was weaving anything, no conspiracies," Ushakov told Russian journalist Pavel Zarubin, who is close to the Kremlin and has previously interviewed Putin. "Moreover, no one even had that in their minds, none of these three leaders had that," Ushakov said.

"Everyone understands the role that the United States, the current administration of President Trump and President Trump personally play in the current international arrangements," Ushakov said in a video posted by Zarubin to his Telegram channel.

Kim, Xi and Putin gathered for the military parade amid Ukrainian and Western concerns over the collaboration of the three nations in bolstering Moscow's full-scale invasion of Ukraine, ongoing since February 2022.

Putin sent an invitation to meet with Kim on the sidelines of the military parade, according to Putin's top foreign policy aide. The two leaders met after the event, according to a Kremlin readout published Wednesday.

Putin thanked Kim for sending North Korean troops to fight Ukraine's incursion in Russia's western Kursk region last year. "I would like to emphasize that your soldiers fought valiantly and heroically," the president said, according to the Kremlin's readout. "We will never forget the sacrifices made by your armed forces and the families of your military personnel."

In response, Kim said, "As I said during our previous meeting, if there is anything we can do to help Russia, we will certainly do that, and we will regard this as our fraternal duty. We will do everything in our power to assist Russia."

The North Korean Foreign Ministry said in a Wednesday statement that Kim was "enveloped in an atmosphere of the warmest friendship and enthusiastic welcome" on his arrival in Beijing.

Ukrainian and Western governments have accused North Korea of supplying significant amounts of ammunition and troops to support Russia's war, while Kyiv and its NATO backers have identified China as Moscow's prime source of materiel and a vital economic lifeline.

ABC News' Tanya Stukalova, Somayeh Malekian and Kevin Shalvey contributed to this report.