Ukrainian President Volodymyr Zelenskyy has called on countries to attend the Ukraine peace summit in Switzerland this month to realize his peace plan.

Zelenskyy delivered a speech at the Asia Security Summit, also known as the Shangri-La Dialogue, in Singapore on Sunday. Defense ministers and other officials from Asian and Western countries attended the forum.

He claimed that people in Ukraine are frequently facing Russian air strikes, saying, "Imagine nearly 100 drones -- it has happened hundreds of times throughout the war."

Zelenskyy expressed his hope for continued military assistance, including air defense systems. That remark came against the backdrop of Russian forces' intensifying offensive in places including the eastern region of Kharkiv.

The Ukrainian leader said peace is "made possible by diplomacy," and that diplomacy "supports Ukraine's resilience in battles."

Zelenskyy said more than 100 countries and international organizations have confirmed their participation in the peace summit in Switzerland on June 15 and 16. He said, "I invite your region, your leaders and countries to join" so that people in different countries can unite "against one war."

Observers say Zelenskyy is hoping to put diplomatic pressure on Moscow by addressing Asian countries, some of which have a neutral stance on Russia's invasion of Ukraine.

At a news conference after the speech, Zelenskyy said, "the war will last longer" due to China's purported military support to Russia, adding, "That is bad for the whole world."

He said, "I believe that today there are strategic mistakes," and that "you can never support a country that is an aggressor."

He criticized China for urging other countries to refrain from attending the peace summit. Beijing has already declared it will be absent.