( CNN ) -- U.S. drug agents in Thailand took custody of five men wanted in the United States on allegations of being part of a drug ring that sought to traffic in North Korean methamphetamine and other drugs , CNN has learned . The men , who have British , Filipino , Taiwanese and Slovak citizenship , were being flown to New York to face charges , according to a source . Thai authorities announced the arrests after the men were turned over to U.S. authorities . A U.S. law enforcement official said the charges would be made public soon . The men are part of a broader investigation that federal prosecutors made public in September , filing charges against a group of former U.S. and European ex-military men in a murder-for-hire and drug-importation plot . The Drug Enforcement Administration concocted a sting operation and arrested Joseph Hunter , a former U.S. Army sniper trainer nicknamed Rambo , and four others in the sting case . The five more recently arrested were expelled by Thai authorities and put on a DEA plane to New York . Additional details of the charges could n't be learned because they remain under seal . Drug trafficking from North Korea has occurred for decades with at least 50 documented incidents . In previous years , North Korea had been linked to shipments of heroin and methamphetamine , according to the CIA World Factbook . In 2003 , a North Korean ship , Pong Su which was carrying nearly 300 pounds of heroin , was seized along the eastern coast of Australia after a four-day chase . There is n't enough information to determine whether the North Korean government is currently involved in drug trafficking , according to the 2013 International Narcotics Control Strategy Report issued by the U.S. State Department . `` There have been no confirmed reports of large-scale drug trafficking involving DPRK ( Democratic People 's Republic of Korea ) state entities since 2004 , '' it stated . `` This suggests that state-sponsored drug trafficking may have ceased or been sharply reduced , or that the DPRK regime has become more adept at concealing state-sponsored trafficking of illicit drugs . '' The report also highlighted that the `` proximity and availability of precursor chemicals in China likely contribute to the production of methamphetamine within North Korea . '' It alluded to reported transactions between North Korean traffickers and organized crime groups . Corrupt security agents and government officials are likely responsible for transnational drug operations , according to a different report published in North Korean Review in 2010 . There is great difficulty in collecting data or accurate information regarding drug trafficking because of the secrecy in North Korea . So the report 's authors , Minwoo Yun and Eunyoung Kim relied on interviews with 28 North Korean defectors living in China and Thailand as well as various documents . They could not be reached Wednesday for this story . Their report alleges that in the 1980s , the North Korean state `` deliberately chose various transnational crime businesses including drug trafficking '' during economically troubled times . The North Koreans specialized in heroin trade and kept the drug away from the ordinary population . Once the economy veered into famine and economic disaster in the 1990s , individuals desperate to survive turned to private drug enterprise , according to Yun and Kim 's report . Corrupt agents and officials sold drugs to transnational organized crime operations through the North Korea-China border , they wrote . Family members also became private drug traffickers , they added . After poppy production failed due to weather , methamphetamine became more popular , according to a 2007 Drug Trafficking and North Korea report prepared for the U.S. Congress . One of the interviewees in Yun and Kim 's report said that the city of Hamhueng is the center of methamphetamine production , because it produces the country 's chemicals . Internally , North Koreans started using opium instead of hard-to-obtain and pricey medication , according to the report . And recreational drug users are more likely wealthy businessmen or members of the Party , according to South Korean media . More recently , methamphetamine is more widely used in North Korea as stricter China border controls forced drug producers to seek a local market for `` ice , '' according to a report in the Spring 2013 edition of the journal North Korean Review .
5 men arrested in Thailand are being flown to the United States , he has said . They are accused of trafficking North Korean drugs , a report says . The arrests are part of a broader investigation made public in September . North Korea has been trafficking drugs since the 1980s , he says .