TOKYO (AP) — A big question looms as the leaders of Japan and South Korea head to Europe next week: Will they finally meet?

Friction over Japan’s brutal colonization of Korea in the first half of the 20th century has prevented a summit between Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-hye since they both took office more than a year ago.

Japan is pushing for a three-way meeting between Park and U.S. President Barack Obama. All three will be attending the March 24-25 Nuclear Security Summit in the Netherlands.

U.S. officials have urged Asian allies Japan and South Korea to improve ties and promote healing on issues of history.