The United States says that North Korea’s construction of a nuclear reactor goes against U.N. resolutions.

State Department Deputy Spokesman Mark Toner told reporters on Tuesday that the North’s uranium enrichment program and construction of a light water reactor violate U.N. Security Council resolutions and its commitments under a 2005 joint statement.

Toner made the remark after he was asked to comment on a Washington Post report that said the North has made rapid progress on the construction of a new nuclear reactor. The report said work has been nearly complete on the outside walls of the reactor building, citing an analysis of recent satellite images.

The daily quoted a former U.S. nuclear negotiator as saying that the reactor building could be completed within six to 12 months.