The US has sanctioned a Singaporean shipowner already wanted by the Federal Bureau of Investigation over his dealings with North Korea.

The US Treasury Department announced on Friday sanctions against Kwek Kee Seng, his Taiwanese business associate Chen Shih Huan, Marshall Islands-registered New Eastern Shipping and two other companies.

Kwek is accused of using the 3,912-dwt Courageous (built 1987) — seized by the US government last year — to deliver petroleum products to North Korea.

“[North Korea's] long-range ballistic missile launches, including over Japan, demonstrate a continued disregard for United Nations Security Council resolutions,” treasury under secretary for terrorism Brian Nelson said in a statement.

“The United States will continue to enforce multilateral sanctions and pursue [North Korea’s] sanctions evasion efforts worldwide, including by designating those who support these activities.”

The US government alleges Kwek and New Eastern acquired the ship in 2019 and arranged for it to carry gasoline to North Korea in defiance of US and United Nations sanctions.

The Courageous made ship-to-ship transfers to North Korean vessels and made at least one direct shipment to the west coast port city of Nampo, the US said.

It also engaged in a number of so-called deceptive shipping practices, moves identified by the US as red flags for sanctions-evasion behaviour in 2020 and routinely reiterated to the industry by government officials as things to look out for while carrying out due diligence.

It said the Courageous disabled its automatic identification system, conducted ship-to-ship transfers at night and made unnecessary detours in order to hide the origin of it cargo.

Kwek was said to have coordinated the transfers and supervised the vessel during its delivery to Nampo, while Chen is described as an associate of Kwek's and helped facilitate crew payments.

The US also sanctioned two other Singapore-based companies connected to Kwek, Anfasar Trading (S) and Swanseas Port Services.

Kewk is also wanted for conspiring to launder the money made in the North Korean shipments through US banks using front companies.

The Courageous was first detained in Cambodia in 2020. The US took custody of the ship and filed for asset forfeiture in April 2021.

A federal judge awarded the US the ship in July 2021.