The U.S. has issued sanctions against two North Korean government officials tied to Pyongyang’s ballistic weapons development program.

The Treasury Department announced sanctions against Ri Pyong Chol and Kim Jong Sik in which any U.S. assets they possess will be frozen and they will be barred from conducting business with Americans, according to NPR. It is uncertain whether either of the men have U.S. assets.

"Kim Jong Sik reportedly is a key figure in North Korea's ballistic missile development, including efforts to switch from liquid to solid fuel," according to the Treasury Department. "Ri Pyong Chol is reported to be a key official involved in North Korea's intercontinental ballistic missile development."

Ri previously was an air force general and appears to be a critical figure among the North Korean’s Working Party. Sik has experience as a civilian aeronautics technician, but he now “wears the uniform of a military general,” according to Reuters.

"Treasury is targeting leaders of North Korea's ballistic missile programs, as part of our maximum pressure campaign to isolate the DPRK and achieve a fully denuclearized Korean Peninsula," Treasury Secretary Steve Mnuchin said in a statement.

This news comes just after the United Nations Security Council unanimously agreed to implement stricter sanctions against North Korea in response to Pyongyang’s latest ballistic missile test last month.

The new sanctions will slash North Korea’s oil imports, require North Koreans working abroad to return to North Korea within 24 months to deprive the nation of foreign currency, and crack down on North Korea’s exports.

The Obama administration also issued sanctions against North Korean individuals in 2016.