The United States Treasury Department has issued sanctions against two officials it describes as "key leaders of North Korea's unlawful weapons programs".
The sanctions against Kim Jong Sik and Ri Pyong Chol block them from any property or interests in property within US jurisdiction and prohibit them from transactions with American citizens.
The US Treasury said the men are senior officials in North Korea's Munitions Industry Department.
Treasury Secretary Steven Mnuchin said the sanctions are part of the United States' "maximum pressure campaign" to isolate North Korea and "achieve a fully denuclearised Korean Peninsula".
The United Nations Security Council unanimously approved tough new sanctions against North Korea on Friday in response to its latest launch of a ballistic missile, which Pyongyang says is capable of reaching the US mainland.
Baik Tae-hyun, spokesman of South Korea's Unification Ministry, expressed hope on Wednesday that the continuing campaign of sanctions and pressure will eventually force North Korea into "making the right decision" and engaging in dialogue over its nuclear program.
Mr Baik noted it was the seventh time the US Treasury has imposed unilateral sanctions against the North since the start of President Donald Trump's administration.
The spokesman also pointed out that the two North Koreans had already been under UN Security Council sanctions.