Volodymyr Zelensky made the statement in a speech to a defence conference in Sweden on Sunday, the Reuters news agency reported.
Speaking via video link from Kyiv, Ukraine's head of state said: "Even Russia can be brought back within the framework of international law."
"Its aggression can be defeated," Zelensky added.
Ukraine's president also told the annual Society and Defense conference in Sälen that Europe must develop joint weapons production to ensure that the continent can "preserve itself" under any global situation that might arise, the Reuters news agency reported.
"Two years of this war have proven that Europe needs its own sufficient arsenal for the defence of freedom, its own capabilities to ensure defence," Zelensky said.
On Wednesday, Polish Prime Minister Donald Tusk called on the European Union to step up its arms production, warning that Russia could attack Europe "in the next few years," if the Kremlin achieves a clear "military advantage," according to news outlets.
Monday is day 684 of Russia’s war on Ukraine.
Russia invaded Ukraine on February 24, 2022, launching the largest military campaign in Europe since World War II.
Source: president.gov.ua, Reuters, Ukrinform, PAP, The New Voice of Ukraine