Middle East:The Sunni-Shia fault line across the Islamic world is ancient, but today it is being deepened deliberately and dangerously, writes Mary Fitzgerald, Foreign Affairs Correspondent.
The people of Mu'tah were accustomed to seeing bands of Shia pilgrims tramping through the dusty streets of their town in the scrubby desert of southern Jordan. The nearby tomb of the Prophet Muhammad's cousin, Ja'far Al-Tayyar, slain there during a battle with Byzantine forces in the early days of Islam, is an important Shia shrine, drawing thousands of pilgrims every year for the holy day of Ashura.
They would come from neighbouring Iraq, Lebanon, the Gulf, Iran, and even as far away as south Asia. Then Iraq was invaded and everything changed. After Saddam Hussein was hanged, the dwindling number of pilgrims dropped even further. "This year you could count them on one hand," says the caretaker.
"There are big tensions now because of Iraq. People are angry because of what happened to Saddam and maybe the Shia are afraid to come here as a result."
Shia Iraqi exiles living in predominantly Sunni Jordan tell a different story. They tell of security guards preventing Shia from observing rituals and chanting at the shrine, warning them of deportation if they do.
They tell of border officials asking if they are Sunni or Shia on arrival. They point out increasingly shrill newspaper articles, like the one in the pro-government daily Ad-Dustour warning of a conspiracy to spread Shiism from India to Egypt. Or mosques where clerics rail against alleged Shia perfidy and worshippers are handed pamphlets purporting to tell "everything you need to know about the Shia".
Rumours abound of Shia proselytising and plans to build a mega-mosque for Shia, funded with Iranian money, on a prime piece of land in Amman.
It's not just confined to Jordan, strained as the tiny kingdom is with almost one million Iraqi emigres. The empowerment of Iraq's Shia has bred resentment in many quarters of the Arab world, making Sunni regimes jittery and more fearful of their own beleaguered Shia populations.
Iran's rising influence is also a huge factor. As tensions escalate between Tehran and Washington, concerns about Iran's intentions in the region have taken on a distinctly sectarian hue, with Sunni clerics and US-allied governments fanning animosities rooted in centuries of theological, political and ethnic rivalry.
Three years ago Jordan's King Abdullah warned of the emergence of a "Shia crescent" across the region. In a television interview last year Egyptian president Hosni Mubarak was blunt, saying: "Most of the Shia are loyal to Iran, and not to the countries they are living in."
Earlier this year King Abdullah of Saudi Arabia denounced what he called Shia proselytising and attempts "to diminish [ the Sunnis'] historical power".
The Sunni-Shia fault line is not new. Beginning with a 7th century dispute over who was entitled to succeed the Prophet Muhammad as head of the nascent Islamic empire, the resulting schism fed into another rift - now at the heart of the region's powerplay - between ethnically Persian Iran, which became Shia, and the Arab swathe of the Middle East, which became predominantly Sunni.
An article written earlier this year by the editor-in-chief of Al- Ahram, Egypt's leading pro-government newspaper, is typical of the rhetoric sweeping predominantly Sunni states. "Iran is active in spreading Shiism even in the countries which don't have a Shia minority . . . to revive the dreams of the Safavid," wrote Osama Saraya, referring to the Persian dynasty which ruled Iran for more than two centuries and enshrined Shiism as the state religion.
"Is this about Shiism or Iran, or a mix of the two? It's not quite clear, and often the two are conflated in this upsurge of sectarian feeling," says Joost Hiltermann, Middle East director of the International Crisis Group.
Iraq's vicious sectarian war, along with rising Sunni-Shia tensions in Lebanon and to a lesser degree in Bahrain and Saudi Arabia, have made Muslims elsewhere more conscious than ever before of their own sectarian identity, says Vali Nasr, a senior fellow at the Council on Foreign Relations and author of The Shia Revival: How Conflicts Within Islam Will Shape the Future.
This is borne out in a recent Pew survey, which found that majorities in seven countries, including Pakistan, Egypt, Lebanon, Kuwait and Tanzania, believe Sunni-Shia tensions are a growing problem for the Muslim world, and are not limited to Iraq. Near majorities in four other countries, including Turkey, agreed.
Where this heightened sense of sectarian identity may lead is grounds for much concern, with some fearing that the Iraq war could spill into a wider Sunni-Shia conflagration.
Washington's increasing bullishness towards Iran is another worry. "The danger is that the US is now coming in the middle of all this and encouraging it as a way of forming an alliance against Iran," says Vali Nasr, echoing suspicions raised by Shia clerics and Mahdi Akef, leader of the Muslim Brotherhood, the world's most influential Sunni political movement.
The problem with this strategy is that it leaves the US with some unlikely bedfellows - extremist Sunni jihadists whose loathing of the West is often surpassed only by their hatred for Shia, whom they consider heretics.
Last January a Kuwaiti cleric influential in jihadist circles ranked Iran ahead of the US and Israel in a hierarchy of villains, decrying the "Safawi enemy that seeks the destruction of Islamic civilisation". The month before, a senior cleric in Saudi Arabia pronounced Shia "more dangerous than Jews and Christians".
Manipulating sectarian tensions is a dangerous game, says Diaa Rashwan, an analyst at the Al-Ahram Centre for Political and Strategic Studies in Cairo.
"Some regimes have allowed people to talk and write about the Shia like this, some have even encouraged it, but sectarianism is not something you can easily control. It taps into feelings that can turn very primitive and encourages fanatics on both sides. To encourage it is to play with fire."