The U.S. government and security officials have reportedly concluded that North Korea’s nuclear technology capabilities are significantly more advanced than those of Iran.

The New York Times on Tuesday quoted Gary Samore, chief nuclear adviser for U.S. President Barack Obama, as saying that the North Korean nuclear program appears to be much more advanced and efficient than the Iranian program.

The paper said that the North’s revelation of its new uranium enrichment plant to a visiting Stanford University professor in November suggests that Pyongyang has a sophisticated network of other secret sites --- and perhaps a fully operating uranium enrichment plant --- elsewhere in the country.

The paper said that North Korea has evaded layers of international economic sanctions and efforts to intercept weapons shipments by sea and air --- efforts that have accelerated following the U.N. Security Council’s passage of a resolution condemning North Korea’s nuclear test last year.