The United States said Friday North Korea's latest set of missile tests was not constructive, and that Pyongyang should devote its energies to meeting disarmament obligations. VOA's David Gollust reports from the State Department.

The Bush administration says North Korea broke no international agreement with its reported test firing Friday of three or four anti-ship missiles.

But the White House said the action was not constructive, and that Pyongyang should focus on meeting commitments under the six-party nuclear accord, including providing a declaration of its nuclear holdings and activities

The missile tests came a day after the North expelled several South Korean officials from a joint north-south industrial site in apparent reaction to the tougher line on North Korea by the new government in Seoul.

In another development Friday, North Korea, through its state-run news agency, threatened to stop the disabling of its nuclear complex at Yongbyon, because of what were termed unreasonable U.S. demands.

In a talk with reporters however, State Department Sean McCormack said the Bush administration is not about to give up on the six-party process despite the week's events.

He said considerable progress has been made on the disablement of the Yongbyon reactor, which produced the plutonium for North Korea's small weapons arsenal.

McCormack said while the promised declaration is now nearly three months late, the administration believes the diplomatic process is still viable and has set no cut-off date for its completion:

"We all view that there's life left in diplomacy here and we're working hard to make it succeed," he said.  "We're beyond the deadline that the parties had set for themselves, and so we'd like to see this move forward as quickly as possible. But you've also heard the Secretary [of State Rice] say that she hasn't circled any dates on the calendar in that regard. We're going to engage in patient diplomacy here, but the North Koreans need to move it forward."

North Korea agreed more than a year ago to give up its nuclear program, including weapons, in exchange for aid and diplomatic benefits from the other parties to the talks including the United States, South Korea, Russia, Japan and China.

The declaration, which was due at the end of last year, has emerged as a key sticking point.

The United States insists that it cover any nuclear cooperation North Korea may have had with other countries, and address a uranium enrichment project Pyongyang is believed to have secretly conducted.

In its statement Friday, the state-run North Korean news agency said Pyongyang never enriched uranium or rendered nuclear help to any other country.

It warned that U.S. efforts to, in its words, "cook up fictions" on the issue could seriously affect the Yongbyon disablement.