A U.S. Treasury Department official has hinted that he intends to step up financial pressure on North Korea and Iran.

Acting U.S. Treasury Under Secretary for Terrorism and Financial Crimes David Cohen said during a Senate hearing on Wednesday that he plans to focus efforts on addressing issues related to North Korea and Iran. He made the remark after he was questioned on ways to prevent the proliferation of weapons of mass destruction.

Cohen said that significant progress was made in terms of applying financial pressure on the North and Iran thanks to U.N. Security Council resolutions and cooperation from private organizations.

Deputy Assistant Secretary for Terrorist Financing and Financial Crimes Daniel Glaser also attended the hearing. Glaser said that active financial pressure on the North and Iran had hampered the two nations’ efforts to secure materials needed to develop nuclear weapons.