WASHINGTON - President George W. Bush on Tuesday expressed "deep concern" about Iran and said Tehran would become more dangerous if it learned how to enrich uranium for nuclear weapons.

"Iran is dangerous, and they will be even more dangerous if they learn how to enrich uranium," Bush said in comments after meeting with Italian President Giorgio Napolitano at the White House.

Bush said he looked forward to working with the Italian leader to "figure out ways we can work together to prevent this from happening for the sake of world peace."

Critics have accused Bush of ratcheting up his rhetoric against Iran even after being made aware in August that Iran may have stopped its nuclear weapons program.

A National Intelligence Estimate released last week said Iran had halted its nuclear weapons program in the fall of 2003.

The report also said Iran was continuing to develop technical capabilities that could be applied to producing nuclear weapons if Tehran made a decision to take that route, citing its civilian uranium enrichment program as an example.

Responding to the report, Bush insisted last week that Iran remains dangerous and urged continued international pressure. But Democrats in Congress said the report showed the administration has overstated its accusations.

Iran said the report as a vindication of its long-standing claim that its nuclear program had only peaceful aims such as electricity generation.