North Korea is ramping up efforts to deploy information technology workers overseas as it increasingly relies on cyberattacks and other online crimes to funds its weapons programs, US and South Korean officials said, anticipating the easing of the isolated country’s strict Covid lockdown.

“This is a growth industry, because as we see the DPRK potentially opening up borders, they could be dispatching additional laborers to all parts of the world to generate revenue,” said Jung Pak, the US deputy special representative for the Democratic People’s Republic of Korea, the country’s formal name. “We think it’s actively getting worse.”

This week, the US Treasury Department sanctioned four entities linked to North Korea’s military and intelligence services, as well as one North Korean based in the Russian city of Vladivostok who received cryptocurrency payments from North Korean tech workers.

Read more: US Urges Countries to Return North Koreans Working Illegally

Pyongyang, forced to shift tactics in response to sanctions programs targeting its nuclear weapons efforts, is increasingly relying on thousands of North Korean programmers who were sent abroad, mainly to China and Russia, before the regime shut its borders during Covid-19, according to the US and South Korea.

They say these in-demand workers can make as much as $300,000 a year, working abroad — often remotely through freelance platforms with falsified or stolen identification — and can assist in enabling cyber attacks and cryptocurrency thefts that helped North Korea earn an estimated $1.7 billion in 2022.

US efforts to sanction North Korea — including at the United Nations — have done little to halt leader Kim Jong Un’s weapons program, with the country launching more than 70 ballistic missiles last year.

One of the main reasons North Korea can continue these efforts is because China and Russia continue to protect North Korea in the United Nations Security Council, as well as host the bulk of the country’s overseas information technology workers as they seek more revenues, Pak said, adding that Beijing should use its leverage to pressure Pyongyang.

“The elephants in the room, obviously, are Russia and China,” Pak said. “It’s extremely difficult to shape the DPRK’s behavior if Russia and China continue to shield it from overwhelming international condemnation of their ballistic missile and nuclear weapons activities.”

Although North Korea has also sent out manual laborers to work in sectors such as construction, Kim’s government views crypto thefts and IT revenue as a “new frontier,” according to Lee Jun-il, the director general for North Korean nuclear issues at South Korea’s Foreign Ministry.

“Since they closed down their border, and their other revenue streams suffered, they have increasingly concentrated on making money out of cyberspace, and as the cryptocurrency market grows, they find more vulnerabilities in the sector,” Lee said in a phone interview from San Francisco, where he was meeting with Pak and other officials.