The Senate and House intelligence committees
were scheduled to be briefed on Thursday, and several other panels such as the Senate Armed Services Committee
were expected to be briefed as well.
North Korea has been suspected of helping
Syria with a secret nuclear program, but both countries deny it. Pyongyang says it has never spread its nuclear expertise
beyond its borders.
Israeli warplanes bombed a site in Syria
on Sept. 6 that private analysts say appears to have been the site of a reactor, based on commercial satellite imagery taken
after the raid. The site later was razed and wiped clean.
Congress will be presented with evidence
that North Korea was helping Syria construct a reactor similar to its facility at Yongbyon, in the west-central part of the
country, said the government official, who spoke on condition of anonymity because of the sensitivity of the matter. That
reactor has in the past produced a small amount of plutonium, which can be a component in nuclear weapons.
One senior administration official said
Thursday's briefing was scheduled because the intelligence community had been deluged for months with congressional requests
for information about North Korean
activity in Syria and the Israeli airstrike and felt it was now time to brief lawmakers.
The official said, though, that there were
concerns that the revelations if leaked or made public could encourage opponents of the administration's attempts to negotiate
an end to North Korea's
nuclear weapons program. U.S. diplomats are pressing North Korea to come clean about its nuclear cooperation with Syria
as part of those talks but have had little success.
At the same time, Middle East experts in
the administration are worried that the timing of the briefing might upstage visits to Washington this week by Jordanian King Abdullah II and Palestinian President Mahmoud Abbas and
hurt Arab-Israeli peace prospects with allegations of nefarious activity by an Arab nation with the aid of North Korea, the
The official spoke on condition of anonymity
to discuss elements of the classified briefing.
Moon Tae-young, the chief spokesman at the
South Korean Foreign Ministry in Seoul, said his ministry would not comment on a media report on intelligence affairs.
White House National Security Council spokesman
Gordon Johndroe said late Tuesday: "The administration routinely keeps appropriate members of Congress informed of national
security and intelligence matters, but I'm going to decline to comment on any specific briefings."
Speculation about a possible release of
information has been building, particularly in the Israeli media, for more than a week, with some reports suggesting that
the briefing would include intelligence gathered by Israel and that the Israeli government had signed off on its being shared.
Another official said Thursday's presentation
would be a compilation of intelligence from more than one source that has been carefully analyzed over a period of months
and by its nature comes with caveats.
Under an agreement reached last year with
the United States, China, Japan, South Korea and Russia, the North is required to give a full account of its nuclear programs, including whether it spread nuclear
North Korea claims it gave the nuclear declaration
to the U.S. in November, but U.S. officials say the North never produced a "complete and correct" declaration.
The Capitol Hill briefing also comes the
same week a U.S. delegation went to North Korea to press the regime for a detailed list of its nuclear programs, the latest
sticking point at international nuclear disarmament talks.
The leader of the delegation is expected
to report back to Washington on Friday.
The U.S. recently has stepped back from
its push for a detailed declaration addressing the North's alleged secret uranium enrichment program and nuclear cooperation with Syria. Now, the U.S. says it wants the
North to simply acknowledge the concerns and then set up a system to verify the country doesn't continue such activity in
President Bush defended the plans over the weekend during a
meeting with new South Korean President Lee Myung-bak, saying North Korea had the burden of proof under the agreements.
The Wall Street Journal first reported Tuesday that U.S. intelligence
officials would tell the committees that North Korea was helping Syria build a plutonium-fueled reactor.