Meanwhile, the Japanese prime minister has sent a tribute to the controversial Yasukuni war shrine.
Since 2013, Abe has been sending offerings there instead of going in person.
But the site was visited today by a member of Abe's Cabinet, Eto Seiichi, and another group of politicians are scheduled to go on Friday.
South Korea's foreign ministry expressed deep regret over those gestures, saying they are an attempt to justify Tokyo's wartime atrocities.
The Yasukuni shrine commemorates some 2.4 million Japanese war dead as well as 14 class-A war criminals.