This Feb. 17, 2021 file photo, provided by the U.S. Department of Justice, shows three North Korean hackers charged by the U.S. government with criminal cyber activities of attempting to steal a total of $1.3 billion in cash and cryptocurrency from banks and businesses around the world. Yonhap

Top South Korean, U.S. and Japanese nuclear envoys on Friday agreed to redouble joint efforts to block North Korea's nuclear and missile program financing through cryptocurrency theft, according to Seoul's foreign ministry.

They also agreed to strengthen international cooperation to foil the secretive North's illicit trade via maritime routes.

The move came as Kim Gunn, special representative for Korean Peninsula peace and security affairs, had phone consultations with his American and Japanese counterparts ― Sung Kim and Takehiro Funakoshi ― on ways to deal with the North's continued provocations highlighted by a string of ballistic missile launches.

Concerns have also grown that Pyongyang may conduct its seventh nuclear test in the near future.

According to a U.N. Security Council report released in April, the North is suspected of having stolen as much as $400 million worth of cryptocurrency in 2021.

The three sides also agreed to further strengthen international cooperation to prevent attempts by North Korea in evading sanctions, such as through illicit ship-to-ship transfers of goods. (Yonhap)