Moderate Muslim states must form an "alliance of moderation" to counter Iran and challenge its influence, UK prime minister Tony Blair has urged.
He called on the world to "wake up" to the monumental struggle between the forces of moderation and extremism.
At the end of his Middle East tour, Mr Blair said the ideological battle was the challenge of the 21st Century.
His call comes as he was criticised by Iraq's vice-president on the issue of troop withdrawal from Iraq.
Speaking in New York, Tareq al-Hashemi suggested Mr Blair had supported his idea of announcing a timetable for withdrawal, but was then "brainwashed" into changing his mind by US President George Bush.
President Bush has so far refused to set a timetable for troop withdrawals.
Mr Blair has been on a tour of the Middle East, visiting Turkey, Egypt, Iraq, the West Bank and Israel.
In a speech to British and United Arab Emirates businessmen in Dubai, Mr Blair said a new partnership was possible with Iran and Syria, if they were prepared to play a constructive role in the Middle East.
But he warned: "We must recognise the strategic threat the government of Iran poses - not the people, possibly not all of its ruling elements, but those presently in charge of its policy.
"They seek to pin us back in Lebanon, in Iraq and in Palestine. Our response should be to expose what they are doing, build the alliances to prevent it and pin them back across the whole of the region."
He said achieving this would need the support of moderate Middle Eastern countries, but his spokesman later said it was not a call for a confrontation between the two Muslim traditions - Sunni and Shia.
Mr Blair, who is due to step down as prime minister next year, said: "We have to wake up. These forces of extremism based on a warped and wrong-headed interpretation of Islam aren't fighting a conventional war, but they are fighting one against us.
"And 'us' is not just the West, still less simply America and its allies. 'Us' is all those who believe in tolerance, respect for others and liberty.
"We must mobilise our alliance of moderation in this region and outside it to defeat the extremists."
During his tour, Mr Blair has met Turkish Prime Minister Recep Tayyip to reassure him of the UK's support for Turkey's bid to join the EU.
Mr Blair has been on a tour of the Middle East
And he has met Palestinian leader Mahmoud Abbas and Israeli Prime Minister Ehud Olmert to discuss the peace process.
In his speech, he set out three priorities to restore momentum to that process, including an early meeting between the two leader and, a relaunch of the political process leading to a two-state solution.
He also called for an office of president of Palestine, which should be given the capacity to improve the lives of the Palestinian people.
It is hoped a stronger role would allow international aid to be channelled through Mr Abbas - bypassing Hamas, which holds a majority in the Palestinian parliament.
The Palestinians have also been suffering under an international aid boycott since Hamas, which refuses to recognise Israel or give up its armed struggle, was elected to a majority of seats in January's parliamentary poll.