Experts see indications of possible North Korean activity at a mysterious military site in Myanmar that, by some accounts, may be linked to chemical arms.

The Burmese government last week sentenced five local journalists to a decade of hard labor after they were declared guilty of airing state secrets with their early 2014 report about a secret military facility in the central Magwe region. The investigative report in the now-defunct Unity journal said the complex was manufacturing chemical-warfare materials.

While expert opinion is divided about whether the plant is producing chemical weapons, some specialists believe it likely that North Korea is involved in some capacity, the Bangkok Post reported on Sunday.

"It's not a chemical weapons factory, but reportedly a factory where they produce aluminum casing for missiles, and 'the Chinese technicians' they mention in the [Unity] article are most likely North Koreans," said longtime journalist Bertil Lintner, who has reported extensively on North Korea.

Jeffrey Lewis, an East Asia nonproliferation expert who has co-written about the chemical weapon possibilities of the military site, told the Post he was particularly intrigued by detected evidence of foreign workers. "[The Burmese Directorate of Defense Industries] has been sanctioned for dealing with North Korea, and this site appears similar to another location near Minbu where North Koreans are believed to live and work," Lewis said.

"Working from satellite images, it would appear that DDI's activities are expanding, not contracting, despite promises to stop any illicit programs and cooperation with North Korea," said Lewis, who directs the James Martin Center for Nonproliferation Studies' East Asia Nonproliferation Program.

Dan Kaszeta, a former U.S. Army chemical weapons officer, said if Myanmar were producing chemical arms, it likely would have a developed a testing and training program for their use -- something not yet in evidence.

"A strong indicator is some kind of testing regime to see if weapons actually work," Kaszeta said. "It seems unlikely that a country would go to the massive effort of making chemical weapons without seeing whether their chosen delivery mechanisms work."

Myanmar has signed but not yet ratified the Chemical Weapons Convention.