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By Matt Spetalnick

WASHINGTON, April 29 (Reuters) - President George W. Bush said on Tuesday he released U.S. intelligence about suspected North Korea-Syria nuclear collusion to put pressure on Pyongyang and send a message to Iran that it could not hide its own nuclear program.

Bush broke months of silence on the matter after his administration went public last week with accusations that Syria had been building a secret nuclear reactor with North Korean help when the facility was bombed by Israeli warplanes last September.

He said the disclosure, including photos and other information the CIA insisted showed the facility's potential for nuclear weapons purposes, was meant to "advance certain policy objectives."

"One would be to the North Koreans, to make it abundantly clear that we may know more about you than you think," Bush told a news conference in the White House Rose Garden.

Syria has denied it was building a reactor and instead accused Washington of involvement in the air attack by Israel, a staunch U.S. ally widely believed to have the Middle East's only nuclear arsenal.

The United Nations' International Atomic Energy Agency has criticized the United States for waiting until this month to share its intelligence and U.S. lawmakers have also complained about the delay.

A diplomat close to the U.N. nuclear watchdog and outside analysts have said the U.S. disclosure did not amount to proof of an illicit arms program because there was no sign of a reprocessing plant needed to convert spent fuel from the facility into bomb-grade plutonium.

Under a six-nation deal reached with North Korea in September 2005, the poor, communist state committed to abandon all nuclear weapons and programs in return for economic aid and diplomatic benefits.

In return, Washington is to drop two sets of sanctions stemming from Pyongyang's presence on the U.S. state sponsors of terrorism list and the U.S. Trading With the Enemy Act.

But the agreement has been stalled by Pyongyang's failure to produce a declaration of its nuclear programs that was due at the end of last year.

INTELLIGENCE WITHHELD

Bush said the intelligence had been withheld at first because of a risk of "confrontation" or "retaliation," an apparent reference to a possible Syrian military response to the Israeli airstrike, but that such concerns had receded.

He acknowledged the disclosure was intended to pressure North Korea to come clean on all of its nuclear activities and said it was also meant to send a tough message to Syria, which the United States has tried to isolate diplomatically.

"And then we have an interest in sending a message to Iran and the world for that matter about just how destabilizing nuclear proliferation would be in the Middle East," Bush said.

Washington is leading an international campaign against Iran over a nuclear program the West suspects is aimed at developing nuclear weapons. Tehran insists it wants nuclear technology for peaceful civilian purposes.

With 10 months left in office, Bush is making a push to resolve the long-festering dispute over North Korea's nuclear program to try to forge a foreign policy legacy that encompasses more than the unpopular war in Iraq.

The administration's release of the intelligence, including briefings with U.S. lawmakers, was widely seen as a bid for support from members of Congress angry about having been kept in the dark about the suspected Syrian-North Korean link. (Editing by David Alexander and John O'Callaghan)

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