"I view this report as a warning signal that they had the programme, they halted the programme," Bush said addressing a press conference.

"The reason why it's a warning signal is they could restart it," he said.

The National Intelligence Estimate (NIE) released on Monday cited that Tehran had halted its nuclear weapons programme in late 2003 and that the programme had not restarted as of mid-2007.

Rejecting the notion that he is dis-spirited because of the credibility that he faces over the Iranian nuclear issue in the wake of report, Bush said there is nothing in the findings that can change his assessment of Tehran.

"I'm feeling pretty spirited -- pretty good about life. And I made the decision to come before you so that I could explain the NIE. And I have said Iran is dangerous. And the NIE doesn't do anything to change my opinion about the danger Iran poses to the world," Bush said.

He said the regime and the leadership of Iran are still dangerous and the international community should do the "hard work" to convince Tehran that there is a better way forward.

"The NIE makes it clear that the strategy we have used in the past is effective. And the reason why we need to make sure that strategy goes forward for the future is because, if Iran shows up with a nuclear weapon, at some point in time, the world's going to say, What happened to them in 2007? How come they couldn't see the impending danger?" Bush added.

The president called on US allies to step up pressure on Iran.

"I'm going to use the NIE to continue to rally the international community for the sake of peace. I'm saying that I believed before the NIE that Iran was dangerous and I believe after the NIE that Iran is dangerous," Bush said.

"There's a better way forward for Iran. There's a better way forward for the Iranian people than one in which they find themselves isolated in the world," Bush said.

"Their economy can be stronger. But their leadership is going to have to understand that defiance and hiding programmes and defying IAEA is -- is not the way forward. And my hope is is that, you know, the Iranian regime takes a look at their policies and changes their policies back to where we were prior to the election of Ahmadinejad, which was a hopeful period. They had suspended their programme. They were at the table," Bush said.

The President said he spoke to his Russian counterpart Vladimir Putin on Tuesday and discussed the Iranian nuclear issue.

"...We did spend a lot of time on the Iranian issue. And one of the interesting tactical decisions that Russia has made that the US supports is the notion that Iran has a sovereign right to have a civilian nuclear power programme," Bush said of his conversation with the Russian leader.