From illicit drug networks to coal exports to cyber-crime, North Korea has several ways to bankroll its nuclear weapons program .

Much of the effort to deter Pyongyang's ballistic missile tests — the most recent of which occurred Monday — has been focused on long-time ally China . But what's less widely discussed is that poor regulations in peripheral regions such as Africa and Southeast Asia are also contributing to North Korea's revenues.

Earlier this month, Washington warned ministers from the Association of Southeast Asian Nation to cut ties with the pariah state "but it does not appear that ASEAN countries are ready to turn the screws on Pyongyang, at least not yet," Kent Boydston, research analyst at the Peterson Institute for International Economics, said in a recent note.

"Southeast Asia's collective insouciance has helped Pyongyang fly mostly under the radar, fill its coffers, and keep its criminal enterprises afloat."

The overall trade picture between ASEAN and North Korea is part of the problem, said Boydston. "Indeed, DPRK-ASEAN trade is relatively small pickings, but $181 million per year is not nothing."

The fact that North Korea maintains embassies in all ASEAN countries, except for the Philippines and Brunei, is also problematic, he warned, claiming that "North Korean agents are almost surely taking part in some variety of nefarious non-diplomatic actions in all of them."

"It has long been known that North Korea runs its networks of nefarious actors and entities out of its embassies abroad, which United Nations Security Council Resolution 2321 attempted to curtail."

Even without an embassy, Manila was still Pyongyang's third-largest trading partner in 2016 and remains a hub for North Korean methamphetamine, Boydston noted. In 2001 and 2008, Philippine authorities seized large meth shipments, and an international crime syndicate claimed in 2013 to have stashed a ton of the illicit drug on the archipelago state.

Meanwhile, the Philippines' relatively lax anti-money laundering laws featured prominently in a 2016 cyber bank heist in which North Koreans allegedly funneled $81 million from the Bangladeshi Central Bank to Manila , Boydston said.

"The world should be concerned about these non-proliferation and otherwise criminal behaviors as they relate to the Philippines-DPRK relationship, although in (President Donald) Trump's call with (Philippine President Rodrigo) Duterte last month, these specific issues weren't discussed."

Pyongyang's relationship with Southeast Asian countries has made headlines recently following the February assassination of Kim Jong-nam, half brother of North Korean leader Kim Jong-un , in Malaysia and a subsequent Reuters investigation that indicated North Korean agents in Kuala Lumpur ran a military equipment firm called Glocom that violated UN sanctions .