"Tan Wee Beng and his co-conspirators made deliberate efforts to launder money through the US financial system on behalf of North Korea," Treasury Secretary Steven Mnuchin said in a statement. "The US government will not overlook these deceptive practices. We are deeply committed to the final, fully verified denuclearization of North Korea, and Treasury will continue to enforce and implement sanctions until that time."

Tan, 41, is accused of conducting millions of dollars in commodities contracts for North Korea, together with at least one other individual and dating back to at least 2011.

The US Department of Justice unsealed criminal charges against him the same day.

An arrest warrant for Tan was issued by the federal court of the Southern District of New York in August, according to an FBI notice that lists Tan under "Most Wanted."

He is charged with conspiracy to violate the International Emergency Economic Powers Act by doing business with North Korean proliferation entities, bank fraud, conspiracy to commit bank fraud, money laundering, conspiracy to commit money laundering, and conspiracy to defraud the United States.

The Treasury said Tan made a "concerted effort to obfuscate payment origins and structure transactions to avoid regulatory scrutiny," and also "knew of and took efforts to evade financial sanctions on North Korea."

When a wire payment was rejected, Tan and Wee Tiong "orchestrated payment in bulk cash, hand-delivered to a North Korean."

WT Marine is closely related to Wee Tiong, and two of its vessels -- the JW JEWEL and NYMEX STAR -- last year engaged in illicit economic activity linked to the North Korean regime, the Treasury said.

The sanctions freeze the property or interests of the designated entities, vessels and person within the US.

American citizens are also generally banned from dealing with them.

Singapore was the site of the first-ever US-North Korea summit between US President Donald Trump and North Korean leader Kim Jong-un in June. The two agreed that North Korea would work toward "complete" denuclearization of the Korean Peninsula in exchange for security guarantees from the US.

Negotiations to implement the deal have stalled.

Still, a second summit has been in the works, with many expecting it to happen early next year. (Yonhap)