President George W. Bush said on Tuesday the recent U.S. disclosure of suspected North Korea-Syria nuclear cooperation was intended to send a tough message to Damascus and Pyongyang as well as Tehran over their nuclear ambitions.

"We wanted to advance certain policy objectives through the disclosure, 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 White House news conference.

The CIA said a suspected secret Syrian nuclear reactor it alleges was being built with North Korean help had been within weeks or months of completion when it was bombed by Israeli warplanes last year.

The United States last week released photos it said proved its accusations of an illicit arms program. Syria has denied the U.S. charges and accused Washington of involvement in the air attack by Israel, which is believed to have the only nuclear arsenal in the Middle East.

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.

Bush said the information had been withheld at first because of concerns about the risk of "confrontation" or "retaliation," an apparent reference to Syria's possible military response to Israel's strike on its territory.

He acknowledged that the disclosure last week was in part aimed at pressuring North Korea to come clean fully on its nuclear and proliferation activities and said it was also meant to send a stern message to Syria.

"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 added.

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.