Japan should never compromise in negotiations with Russia over the return of the four islands off Hokkaido, a private think tank has proposed.

The policy proposal, unveiled last week by the Japan Forum on International Relations, counters an opinion in circulation among some politicians and bureaucrats suggesting that the two smaller islands should be returned before the two larger ones to facilitate concluding a peace treaty with Russia.

Even though more than 60 years have passed since World War II and half a century since diplomatic ties were restored, the long-standing territorial dispute has prevented the two nations from concluding a bilateral peace treaty to formally end hostilities.