The U.S. government is hosting events involving Japanese and South Korean lawmakers this week to help the Asian neighbors improve bilateral relations that have soured in recent years due to differences over historical issues, according to a U.S. government source.

The State Department has organized a series of events that began Monday in Washington and will include meetings between legislators so they can better understand each other, as well as discussions with officials from the U.S. State and Defense departments, the source said.

During the roughly weeklong series of meetings, the Japanese and South Korean lawmakers will also hold talks with senators and House of Representatives members, according to the source.

The project emerged as Washington works on helping Tokyo and Seoul bridge persistent gaps related to Japan's colonial rule of the Korean Peninsula and World War II, believing close trilateral cooperation is necessary to address North Korea's nuclear weapons and ballistic missile programs.

Among the contentious topics are the issues of wartime labor involving Korean workers, as well as Korean "comfort women" who were forced or coerced into Japan’s wartime brothel system under various circumstances, including abduction, deception and poverty.

Ned Price, a spokesman for the department, told reporters last week that the United States recognizes "the trilateral relationship and trilateral cooperation is indispensable if we are going to effectively confront" the North Korean threat.

"We encourage Japan and (South Korea) to ... continue to address those difficult historical issues, so we can be most effective together when it comes to that trilateral coordination," he said.

Pyongyang has test-launched ballistic missiles in defiance of a spate of U.N. Security Council resolutions, and speculation has been rife that it is preparing to conduct a seventh nuclear test.