New Delhi, Jan. 14 -- South Korean President Lee Jae Myung and Japanese Prime Minister Sanae Takaichi agreed Tuesday to step up cooperation in areas including economic security, defense and searching for the remains of Korean forced laborers.

The two neighbors are both longtime U.S. allies, but their relations have frequently been strained by issues including disputes over their wartime history.

"I believe cooperation between Korea and Japan is now more important than ever and anything else, as we have to continue moving forward to a new, better future amid this complex, unstable international order," Lee said at the outset of the summit.

During a joint news conference after the talks, the leaders said they had agreed to cooperate in a...