The United States on Monday sanctioned a Vietnam-based North Korean on suspicion of supporting North Korea's weapons of mass destruction program in violation of UN sanctions.

The US Treasury Department announced the measure on its website, saying the individual, Kim Su-il, is tied to the North's ruling Workers' Party and an employee of its affiliate, the Munitions Industry Department.

That department, it said, was previously sanctioned by the US and the UN for its involvement in "key aspects" of North Korea's missile program.

"Treasury continues to enforce existing sanctions against those who violate United Nations Security Council resolutions and evade US sanctions on North Korea's unlawful nuclear and ballistic missile programs," Treasury Under Secretary for Terrorism and Financial Intelligence Sigal Mandelker said. "Kim Su Il has violated UNSCRs and supports North Korea's weapons program."

The designation is the latest demonstration of US resolve to continue enforcement of sanctions on North Korea until it dismantles its nuclear and ballistic missile programs.

The action comes after North Korea launched two short-range ballistic missiles last week despite US efforts to resume working-level denuclearization talks in line with a June agreement between US President Donald Trump and North Korean leader Kim Jong-un.

Earlier in the day, US Secretary of State Mike Pompeo said he hopes the working-level discussions will start again "very soon," but he also reiterated Washington's commitment to the pressure campaign.

"These aren't US sanctions. These are UN Security Council resolutions," he said in remarks to the Economic Club of Washington, DC "These are global sanctions put on by every single country, and so we are mindful that we are the steward for enforcing those."

The Treasury said Kim Su-il, 34, works as a trading company official on behalf of the Munitions Industry Department in Vietnam.

As of early this year, he was responsible for exporting North Korean anthracite coal and titanium ore concentrate, and importing and exporting various other goods to earn foreign currency for the Pyongyang regime, it said.

Assigned to Ho Chi Minh City, Vietnam, in 2016, Kim also exported Vietnamese products to China, North Korea and other countries, according to the Treasury.

The designation freezes all property and interests of the individual in US control, and bans all transactions between him and US citizens. (Yonhap)