The U.S. government froze any U.S. assets of a Swiss firm that it accused of involvement in weapons proliferation by North Korea. The company, Kohas AG, and its Swiss chairman, Jakob Steiger, also were banned from trading with any American entity, the Treasury Department said in a statement Thursday. "Kohas AG acts as a technology broker in Europe for the North Korean military and has procured goods with weapons-related applications," the statement said. Kohas and Steiger "have been involved in activities of proliferation concern on behalf of North Korea since the company's founding in the late 1980s." Kohas is an industrial supply wholesaler. Nearly half of the company's shares are owned by a subsidiary of Korea Yonbong General Corporation, which was put on the U.S. weapons-proliferation blacklist last year. "North Korea's efforts to build and sell weapons of mass destruction depend on a vast network, the reach of which extends beyond Asia," Treasury Department terror-financing chief Stuart Levey said. "The Treasury will continue to track and combat this network aggressively to exclude North Korea's illicit activity from the financial system."