Seoul (South Korea): South Korea, the US and Japan called for stronger international support of efforts to ban North Korea from sending workers abroad and curb the North's cybercrimes as a way to block the country's means to fund its nuclear program.

The top South Korean, US and Japanese nuclear envoys met in Seoul on Friday in their first gathering in four months to discuss how to cope with North Korea's growing nuclear arsenal.

The North's recent weapons tests show it is intent on acquiring more advanced missiles designed to attack the US and its allies, rather than returning to talks.

Despite 11 rounds of UN sanctions and pandemic-related hardships that have worsened its economic and food problems, North Korea still devotes much of its scarce resources to its nuclear and missile programs.

Contributing to financing its weapons program is also likely the North's crypto hacking and other illicit cyber activities and the wages sent by North Korean workers remaining in China, Russia and elsewhere despite an earlier UN order to repatriate them by the end of 2019, experts say.

In a joint statement, the South Korean, US and Japanese envoys urged the international community to thoroughly abide by UN resolutions on the banning of North Korean workers overseas, according to Seoul's Foreign Ministry.

The ministry said a large number of North Korean workers remain engaged in economic activities around the world and transmit money that is used in the North's weapons programs.

It said the three envoys tried to call attention to the North Korean workers because the North may further reopen its international borders as the global COVID-19 situation improves.

It is not known exactly how many North Korean workers remain abroad. But before the 2019 UN deadline passed, the US State Department had estimated there were about 100,000 North Koreans working in factories, construction sites, logging industries and other places worldwide.

Civilian experts had said that those workers brought North Korea an estimated US $200 million to $500 million in revenue each year.

We need to make sure that its provocations never go unpunished. We will effectively counter North Korea's future provocations and cut their revenue streams that fund these illegal activities, Kim Gunn, the South Korean envoy, said in televised comments at the start of the meeting.

Sung Kim, the US envoy, said that with its nuclear and missile programs and "malicious cyber program that targets countries and individuals around the globe, North Korea threatens the security and prosperity of the entire international community.

South Korea's spy agency said in December that North Korean hackers had stolen an estimated 1.5 trillion won (USD 1.2 billion) in cryptocurrency and other virtual assets in the past five years, more than half of it last year alone.

The National Intelligence Service said North Korea's capacity to steal digital assets was considered among the best in the world because it has focused on cybercrimes since UN economic sanctions were toughened in 2017 in response to its earlier nuclear and missile tests.

Friday's trilateral meeting will likely infuriate North Korea, which has previously warned that the three countries' moves to boost their security cooperation prompted urgent calls to reinforce its own military capability.

North Korea has long argued the UN sanctions and US-led military exercises in the region are proof of Washington's hostility against Pyongyang.

The North has said it was compelled to develop nuclear weapons to deal with US military threats, though US and South Korean officials have steadfastly said they have no intention of invading the North.

Earlier this week, the United States conducted anti-submarine naval drills with South Korean and Japanese forces in their first such training in six months.

The US also flew nuclear-capable bombers for separate, bilateral aerial training with South Korean warplanes.

North Korea hasn't performed weapons tests in reaction to those US-involved drills. But last month, it carried out a barrage of missile tests to protest the earlier South Korean-US military training that it sees as an invasion rehearsal.

Takehiro Funakoshi, the Japanese envoy, said North Korea's recent weapons tests and fiery rhetoric pose a grave threat to the region and beyond.

Under such circumstances, our three countries have significantly deepened our coordination, he said.

Sung Kim reiterated that Washington seeks diplomacy with Pyongyang without preconditions.

North Korea has previously rejected such overtures, saying it won't restart talks unless Washington first drops its hostile policies, in an apparent reference to the sanctions and US-South Korean military drills.

Many experts say North Korea would still eventually use its enlarged weapons arsenal to seek US concessions such as the lifting of the sanctions in future negotiations.

There are concerns that North Korea could conduct its first nuclear test in more than five years since it unveiled a new type of nuclear warhead last week.

Foreign experts debate whether North Korea has developed warheads small and light enough to fit on missiles.