The Treasury Department on Tuesday sanctioned two officials described as “key leaders of North Korea’s unlawful weapons programs.”

Treasury said Kim Jong Sik and Ri Pyong Chol are senior officials in North Korea’s Munitions Industry Departments. The sanctions will block them from any from any property or interests in property within U.S. jurisdiction, and prohibit them from transactions with American citizens.

Treasury Secretary Steve Mnuchin said the sanctions are part of the U.S.’ “maximum pressure campaign” to isolate Kim Jong Un’s regime and “achieve a fully denuclearized Korean peninsula.”

The United Nations Security Council unanimously approved new sanctions against North Korea on Friday in response to its latest missile launch, which Pyongyang claims is capable of reaching the U.S. mainland.

“It sends the unambiguous message to Pyongyang that further defiance will invite further punishments and isolation.” U.S. Ambassador to the U.N. Nikki Hailey said after the sanctions were passed.

North Korea’s government called the new sanctions “an act of war.”

Baik Tae-hyun, spokesman of South Korea’s Unification Ministry, expressed hope 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.

Baik noted it was the seventh time the U.S. Treasury has imposed unilateral sanctions against the North since the start of President Donald Trump’s administration. Baik also pointed out that the two North Koreans had already been under U.N. Security Council sanctions.

The Associated Press contributed to this report.