The White House says Syria was covertly building a nuclear reactor, with clandestine North Korean assistance, capable of producing plutonium. A statement from the White House, and an unusual release of photographic intelligence, followed briefings for members of Congress about what the White House says were Syria's illicit nuclear activities. VOA's Dan Robinson reports from Capitol Hill.

Calling the issue one of great international concern, the White House says North Korea helped Syria develop and build the reactor, which the White House says was probably damaged beyond repair in an Israeli air strike last September.

"We have good reason to believe," the statement continues, "that the reactor was not intended for peaceful purposes, was carefully hidden from view, and that Syria's government moved quickly to bury evidence of its existence after the Israeli strike," in what the White House statement calls a cover-up.

It says the United States is briefing the International Atomic Energy Agency (IAEA) on the intelligence, and calls on Syria's government to "come clean before the world" regarding its illicit nuclear activities.

Throughout the day Thursday, members of Congress were briefed by CIA Director Michael Hayden and other officials on intelligence about the suspected Syria-North Korea connection.

These briefings, and the White House statement, come as the United States and partners in the six-party negotiations with North Korea attempt to move Pyongyang toward fulfilling its commitment of full disclosure of its nuclear activities, including any proliferation.

North Korea was supposed to have provided a full declaration on its nuclear programs three months ago, including details of any assistance given to or obtained from other countries.

Syria's ambassador to the United Nations, Bashar Ja'afari, on Wednesday issued a flat denial of any cooperation between his country and North Korea.

"We said it many times in the past, that there were no Syrian-North Korean cooperation whatsoever in Syria," said Bashar Ja'afari. "We deny these rumors. This is what I can say with this regard."

Late Thursday, the White House took the unusual step of releasing on a DVD satellite and hand-held camera images of what the U.S. says is the Syrian site targeted by the Israeli air strike.

The images show a building, virtually complete as of August 2007, that intelligence analysts and other experts describe as being similar in construction to North Korea's plutonoium reactor at Yongbyon, which it agreed to dismantle as part of steps to resolve the impasse over its nuclear program. Also shown are statellite images after the Israeli air strike, showing the razing of the remains of the structure by Syria.

The images show a building that has been described by some experts as being similar in construction to North Korea's reactor at Yongbyon, which it agreed to dismantle as part of the six-party talks.

Earlier in the day, lawmakers on Capitol Hill expressed frustration with what they called unjustified delays by the Bush administration in briefing Congress.

Democrat Gary Ackerman, who chairs the House Middle East subcommittee, accused the administration of leaking the information before briefing lawmakers.

"Before any of us was given any information, and prior to the briefing, suddenly it appears in our nation's premier newspapers this morning, information that the administration has chosen selectively to put out, even before members of Congress and chairmen of committees were able to see this," said Ackerman.

Anger was echoed by Democrat Silvestre Reyes, the current chairman of the House Intelligence Committee, and the ranking panel Republican Pete Hoekstra.

Hoekstra said the administration offered no compelling reason for delaying briefings for Congress, but he had this comment on what he heard in the briefing.

"This is a serious proliferation issue, both in the Middle East and for the countries that may be involved in Asia," said Hoekstra.

Thursday's White House statement calls North Korea's cooperation with Syria a dangerous manifestation of Pyongyang's nuclear weapons program and proliferation activities, and says construction of the Syrian reactor was a "dangerous and potentially destabilizing development for the region and the world."

Referring to long-standing U.S. allegations of Syrian support of terrorism, it calls the development a reminder that, often, the same regimes that sponsor proliferation also sponsor terrorism and foster instability, and cooperate with one another in doing so.

The White House statement also draws a connection with Iran, saying the international community is right to be concerned about nuclear activities of Iran and the risks these pose to the stability of the Middle East.

Earlier in the day, the House foreign affairs chairman, Howard Berman, issued a statement calling reported details of North Korean-Syrian cooperation disturbing, but saying he does not believe they provide a reason to suspend the six-party talks with Pyongyang.

The White House statement says the U.S. will work with its partners in the six party Framework negotiations with North Korea to establish rigorous verification to ensure that such conduct and other nuclear activities have ceased.