TOKYO (Kyodo) -- Ukraine's ambassador to Japan has stressed his country needs security guarantees as a condition for a cease-fire in its fight against Russia, amid concerns over U.S. President Donald Trump's conciliatory stance toward Moscow in peace talks.

In an interview with Kyodo News earlier this month, Sergiy Korsunsky, who is set to leave his post in mid-April after five years, expressed hope for continued U.S. support while conveying gratitude for Japan's aid to Ukraine.

Reaching an agreement with Russia that "guarantees Ukraine's security and enables the punishment of war criminals" is essential, Korsunsky said, as the third anniversary of Russia's full-scale invasion approaches next Monday.

Japan and its Group of Seven peers, including the United States under Trump's predecessor President Joe Biden, and like-minded partners provided strong assistance to Ukraine, imposing economic sanctions on Russia.

Trump, who returned to the White House on Jan. 20 with his unilateralist "America First" doctrine, is skeptical about support for Ukraine. He has maintained close ties with Russian President Vladimir Putin since his first four-year term beginning in 2017.

Since Trump and Putin held phone talks on Wednesday, Washington and Moscow have accelerated efforts to end the war in Ukraine, but the move has fueled worries that Kyiv could be forced to accept unfavorable terms and relinquish Russian-occupied territories.

Korsunsky said the United States surely "understands the nature of this war" and clearly recognizes "who began this war and has been killing many people." He added he considers U.S. assistance for Ukraine unlikely to terminate.

Some U.S. officials from Trump's administration have said Ukraine's long-sought-after NATO membership is "unrealistic." Korsunsky argued that such pro-Russian remarks do not reflect the ultimate view of the United States.

Korsunsky, meanwhile, thanked "all Japanese people who have supported" Ukraine, voicing expectation that its technology and past experience in recovering from natural disasters, including earthquakes, can be utilized for Kyiv's future reconstruction.

Japan has hosted over 2,700 Ukrainian refugees since the start of the aggression and around 2,000 of them are still living in the country, according to government data.

Korsunsky said it is important for Ukrainian residents to "contribute to Japan's society as its members" by finding employment and other means, rather than only receiving aid.

As for the Russian-controlled, Japanese-claimed islands off Hokkaido, called the Northern Territories by Tokyo and the Southern Kurils by Moscow, Korsunsky emphasized Ukraine's "full support" for Tokyo's position.

Japan maintains that the four islands -- Etorofu, Kunashiri, Shikotan and the Habomai islet group -- were illegally seized by the Soviet Union soon after Japan's surrender in World War II on Aug. 15, 1945, while Russia says the act was legitimate.

Settlement of the territorial dispute, which has long prevented Tokyo and Moscow from concluding a peace treaty, will be possible "only after a change" of the Russian regime and therefore it "makes no sense" to negotiate with Putin, Korsunsky added.

Korsunsky also said Ukraine has demanded Japan introduce "stricter controls" on the export of electronic devices that it is believed are being diverted into weapon parts by Russia and North Korea, a supporter of Moscow, after obtaining them via third nations.