The Japanese government has been stepping up efforts with the United States and South Korea to urge countries that have been accepting workers from North Korea to no longer do so in a bid to cut off financing for Pyongyang's nuclear and missile development plans, Kyodo News quoted sources as saying on Sunday.

Defying UN Security Council resolutions and warnings from the international community, North Korea has conducted four nuclear tests, most recently in January, as well as rocket launches using ballistic missile technology.

At a time when Japan along with the United States and South Korea remain on alert for a possible fifth nuclear test by the North, the three countries have been trying since spring to root out one of the sources of North Korea's finances -- foreign currency earned by North Korean workers abroad, the sources explained.

Source ; MENA