Special report: Iran Nuclear Crisis

U.S. President George W. Bush, at a White House press conference on Thursday, said that the sanction regime on Iran needs to be strengthened for its defiance on the nuclear issue.

"My view is that we need to strengthen our sanction regime," Bush said.

The United States will work with its European allied to "develop further sanctions," Bush said, adding that he will also discuss the issue with Russian President Vladimir Putin and Chinese President Hu Jintao.

"The first thing that these leaders have got to understand is that an Iran with a nuclear weapon would be incredibly destabilizing for the world. It's in their interests that we work collaboratively to continue to isolate that regime," Bush said.

The Bush administration said Wednesday that it would use a new report by the International Atomic Energy Agency (IAEA) to encourage European and Asian allies to seek a major expansion of sanctions against Iran.

The IAEA report, released on Wednesday, said Iran has expanded its uranium enrichment activities in defiance of UN demands to scrap its nuclear-related programs.

The United States has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. However, Iran has said its nuclear program is for peaceful purposes only and has vowed to continue its uranium enrichment program.

Editor: Yan