Russian President Vladimir Putin visited Iturup, ‌a Japan-claimed island at the end of the Kuril chain near the island of Hokkaido, Russian media said on Thursday, a day after major naval drills ​and a missile firing by ally North Korea.

Moscow and Tokyo never ​signed a formal World War Two peace treaty as ⁠the main hurdle was the unresolved territorial dispute over the islands, which ​Japan calls the Northern Territories.

On the trip, which state news agency TASS ​described as Putin’s first in person to the island chain, he visited the Yasny fish-processing plant on Iturup, after overseeing the navy drills in Russia’s far east.

Japan’s foreign ​minister protested against Putin’s visit on X.

“The northern territories, including Etorofu, ​are Japan’s inherent territory both historically and based on international law,” said Toshimitsu Motegi. “Japan ‌strongly ⁠protests this visit.”

Vesti TV channel images showed Putin in a dark suit, standing in a room looking at two large tuna and halibut on a table, as two officials spoke about fishing and the migratory behaviour ​of fish. He ​also stopped to ⁠try local fish roe.

Read: North Korea fires missile ahead of major US-South Korea drills

“What lovely weather you have there, just like a resort!” Putin told a group ​of Iturup locals. “And we thought you arranged this!” a ​woman, who ⁠appeared to be in her 30s, joked back.

The visit follows Wednesday’s firing of a ballistic missile by ally North Korea, towards waters off the east ⁠of the ​Korean peninsula, days ahead of major joint ​military exercises by Seoul and Washington long denounced by Pyongyang.