NEW YORK -- The office of UN Secretary-General Antonia Guterres on Sunday rejected Japan's claim that he expressed support for a 2015 deal reached between Seoul and Tokyo over the issue of Japan's wartime sexual slavery.

According to press reports, Japan's Foreign Ministry made the claim that Guterres backed the deal, which is deeply unpopular in South Korea, when he met with Japanese Prime Minister Shinzo Abe in Italy on Saturday on the sidelines of a summit of the Group of Seven industrialized nations.

But Guterres' spokesman said the UN chief never expressed support specifically for the 2015 deal.

"The secretary-general and Prime Minister Abe did discuss the issue of so-called comfort women. The secretary-general agreed that this is a matter to be solved by an agreement between Japan and the Republic of Korea," the spokesman said in a note to correspondents.

"The secretary-general did not pronounce himself on the content of a specific agreement but on the principle that it is up to the two countries to define the nature and the content of the solution for this issue," he said.

The 2015 deal, which was reached when impeached former President Park Geun-hye was in office, centered on Japan's admission of responsibility for the crime and plans to pay reparations to the victims. South Korea promised to end the dispute once and for all if Japan fulfills its responsibilities.

But the agreement has been under fire for failing to take the victims' positions into consideration.

Historians estimate that up to 200,000 women, mainly from Korea, which was a Japanese colony from 1910 to 1945, were forced to work in front-line brothels for Japanese soldiers during World War II. Japan has long attempted to water down the atrocity. (Yonhap)