Honour guards hold national flags of Japan and Russia prior to a welcome ceremony for Russia's Defence Minister Sergei Shoigu at the Defence Ministry in Tokyo on May 30, 2019. (KAZUHIRO NOGI / AFP)

TOKYO / MOSCOW - Japan's new Prime Minister Yoshihide Suga spoke with Russian President Vladimir Putin via phone on Tuesday, which was their first conversation since Suga took office earlier this month.

In the talks that lasted about 20 minutes, Suga told Putin that he wants to make progress on peace treaty talks, the Japanese prime minister told reporters after the phone conversation.

In the talks that lasted about 20 minutes, Suga told Putin that he wants to make progress on peace treaty talks, the Japanese prime minister told reporters after the phone conversation

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Putin, for his part, said he is ready to continue dialogue on bilateral issues, according to Suga. The two leaders agreed to hold in-person talks soon.

In a statement, the Kremlin said Putin and Suga discussed possible medical cooperation, including on the development of COVID-19 vaccines.

Japan and Russia have not signed a post-World War II peace treaty due to their rival claims to four Pacific islands, called the Northern Territories in Japan and the Southern Kurils in Russia.

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The Soviet army took the four islands during the final days of World War II. After the collapse of the Soviet Union, the four islands were incorporated into Russia.

The two countries have held rounds of consultations on joint economic activities on the islands in five areas, namely, aquaculture, greenhouse, tourism, wind energy, and waste recycling. They view cooperation as a step toward a peace treaty, but so far no major breakthrough has been made.

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With inputs from Reuters