South Korean President Moon Jae-in and Prime Minister Shinzo Abe spoke by phone Thursday for the first time since Moon took office and agreed to closely cooperate on dealing with North Korea and on building a "future-oriented" relationship, a senior Japanese official said.

Moon did not express a negative view of the 2015 "comfort women" agreement, the official told reporters. Instead, he only told Abe that there are "cautious opinions" circulating in public about the accord, which was signed to put the issue of comfort women to rest "finally and irreversibly," the official said.

Comfort women is Japan's euphemism for women forced to work in Japan's military's brothels before and during the war.