Families of Japanese nationals abducted by North Korea have again demanded a swift resolution of the decades-old issue.

Japan has stepped up its air defences amid rising tensions in Asia after acquiring three advanced F-35 Lightning II aircraft from the United States. The fifth-generation fighter jets will be based at the Komatsu Air Base in Ishikawa, located on the country's west coast just off the Sea of Japan, also known as the East Sea.

The incident, which occurred during a ceremony attended by leader Kim Jong Un, reportedly saw “sections of the warship's bottom crushed.'

Pyongyang has carried out frequent missile tests in violation of United Nations Security Council sanctions and continues to build out its nuclear weapons program. The Kim Jong Un regime insists both are necessary for self-defense, citing "provocations" by the U.S. and its allies.

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Japan's Prime Minister Ishiba Shigeru has met with relatives of Japanese citizens who were abducted by North Korea. He pledged to make his utmost efforts to resolve the issue as soon as possible while gaining cooperation from the international community.

The remarks came after The Wall Street Journal reported that the White House is considering pulling out roughly 4,500 troops and relocating them.

Yi Won-woo, deputy director-general for North American affairs at Seoul's foreign ministry; U.S. Deputy Assistant Secretary of State for China, Japan, Korea, Mongolia and Taiwan Kevin Kim; and Akihiro Okochi,