From Yonhap News:

The U.S. administration announced Wednesday it is freezing the assets of entities linked to the spread of weapons of mass destruction, including… three North Korean-related firms — the Korea Mining Development Trading Corporation, Tanchon Commercial Bank, and the Korea Ryonbong General Corporation. The annex also names four connected to Iran and one to Syria…

Under this executive order, the U.S. would freeze assets not only of the mentioned entities but any person or organization that has past or future transactions with them… A diplomatic source here said, however, that the latest measure was not to be viewed as relating to the nuclear talks. “This is in line with nonproliferation efforts undertaken by the United States all along. It is an overall measure that does not specifically target North Korea,” the source said on condition of anonymity… The executive order was crafted by a nine-member commission, which in March presented 74 recommendations on overhauling the intelligence community and preventing the spread of weapons of mass destruction. [emphasis added]

While the recommendation came in March and was related to WMD proliferation, it will likely be seen as a move to strangle North Korea; it is such a move, but not a targeted one. Without the cooperation of China and South Korea, this is the sort of action the U.S. can take, short of UN resolutions (for what they are worth), and military options.

More on this at the Chosun Ilbo:

A report to Congress has the U.S. assets of the three companies at a total of US$32 million. The measure is also being applied against five Iranian and Syrian companies and bodies. In particular, the presidential order calls for the measure to be applied not just to the eight companies specified, but also to companies and bodies, regardless of nationality, that the State Department judges to be supporting the development and proliferation of nuclear weapons through transactions or cooperation with the eight North Korean, Iranian and Syrian entities…

Despite this explanation, some are wondering — with the measure coming after the U.S. strongly raised the issue of North Korean human rights by inviting North Korean defector Kang Chol-hwan to the White House — whether the U.S. government is creating obstacles to the restart of the six-party talks