George Bush has used the latest stage of his Middle East tour to focus on what he says is the threat Iran poses to world security.
Washington has accused Iran of supporting Hizbollah in Lebanon, Hamas in Gaza and insurgents in Iraq.
Speaking in the United Arab Emirates, the US President urged world leaders to confront this perceived danger.
“Iran is today the world’s leading state sponsor of terror. It sends hundreds of millions of dollars to extremists around the world while its own people face repression and economic hardship at home.”
Gulf states like the UAE, Saudi Arabia and Kuwait are allies of the US, while at the same time important trading partners with neighbour Iran.
Iran has issued a video of an incident last week when the US navy says its ships were harassed by Iranian speedboats. Tehran says it was a routine operation that Washington is exaggerating for propaganda purposes.
Bush visited naval officers at the centre of the row at the US Fifth Fleet based in Bahrain, before flying to the UAE. The next scheduled stops on his tour are Dubai, Saudi Arabia and Egypt.