The Obama administration expanded sanctions against North Korea on Monday by freezing assets of individuals, companies and organizations allegedly linked to support for Pyongyang's nuclear program.
Targeted entities included one variously known as Office 39 or Bureau 39, believed to direct a range of illicit activities in support of the North Korean nuclear program.
In a report this year, the U.S. Army War College's Strategic Studies Institute said Office 39 is involved in the manufacture and distribution of illegal drugs, the counterfeiting of U.S. currency, and the manufacture and distribution of counterfeit cigarettes.
"The crimes organized by Office 39 are committed beyond the borders of North Korea by the regime itself, not solely for the personal enrichment of the leadership, but to prop up its armed forces and to fund its military programs," the institute's report said.
In announcing the new sanctions, the U.S. Treasury Department said President Barack Obama had issued an executive order authorizing action again four North Korean individuals, three North Korean companies and five North Korean government agencies. The order took effect Monday.
Two of the targeted individuals are associated with the North Korean government's General Bureau of Atomic Energy. Ri Hong Sop is believed to be a former head of the Yongbyon nuclear complex; Ri Je Son is believed to be director general of the General Bureau of Atomic Energy.
Secretary of State Hillary Rodham Clinton had announced the administration's intention to expand sanctions against North Korea when she was in Seoul, South Korea, in July. That was in the tense aftermath of the March sinking of a South Korean warship that killed 46 sailors — the worst military attack on the South since the 1950-53 Korean War.
The United States and South Korea blamed North Korea, which has denied involvement and threatened to retaliate if it were to be punished.
Clinton said in July that new U.S. sanctions were meant to warn Pyongyang to resist further military provocations.
North Korea, which tested a nuclear bomb in 2006, is believed to have enough weaponized plutonium for at least half a dozen atomic bombs and last year revealed it has a uranium enrichment program that would give the regime a second way to make nuclear weapons.
Five nations — China, Russia, South Korea, the U.S. and Japan — have been trying for years to negotiate with North Korea to dismantle its nuclear program in exchange for aid and other concessions.
Pyongyang abandoned those talks last year after the U.N. Security Council condemned the regime for carrying out a long-range missile test. Weeks later, North Korea carried out a second nuclear test.