North Korea has been fueling fears of World War 3 with its refusal to terminate its weapons’ development programme.
And the high-profile defector warned Pyongyang continues to support its programme by selling weapons on the black market in spite of the swathe of United Nations sanctions adopted to cut off the rogue nation.
Mr Jong Ho said: “The smuggling is conducted by any and every means you can imagine.
“On the open sea, the Yellow Sea, there are hundreds of fishing boats, both from China and North Korea. All the smuggling is done by these so-called fishing boats.”
The North Korean renegade said he sometimes handed “bags of cash” to ship captains leaving from China to North Korea before he defected in 2014.
He added that the smuggling network was so extensive China – which promised to act as a positive influence on Pyongyang – struggled to put an end to it.
Mr Jong Ho told CNN: “Larger items are mostly done using ships. For example by filing a cargo list where what’s written is different from what is really being shipped.
“All the smuggling is done by these so-called fishing boats. Instead of fishing, they are involved in smuggling and it is very difficult, even for China, to stop these hundreds of fishing boats.”
In 2016, North Korean ship Jie Shun was intercepted before reaching the Suez Canal and was found to be transporting 30,000 PG-7 rocket-propelled grenades hidden under 2,000 tonnes of iron ore.
Ship-to-ship trades with North Korea are banned under a UN Security Council (UNSC) resolution adopted in September.
But reports suggest China supplied Pyongyang with fuel, sparking the furious response of US President Donald Trump.
Mr Trump slammed China for its double-edged behaviour, saying he was “disappointed” by Bejing.
He wrote on Twitter: “Caught RED HANDED – very disappointed that China is allowing oil to go into North Korea. There will never be a friendly resolution to the North Korean problem if this continues to happen!”