Iran Deal Welcomed by Iraq and Syria but Won't Change Course of Conflict

Iran's historic nuclear deal may ease hostility with the West that has fuelled Middle East tensions for decades, but it is unlikely to change the course of conflicts where Tehran and Washington are both awkward allies and enemies.

In Syria, Iran has stood by President Bashar al-Assad, providing military and financial support during four years of civil war, throughout which the United States has said Assad must go.

In neighbouring Iraq, Tehran and Washington support Prime Minister Haider al-Abadi's government in its battle against Islamic State, although their historic hostility means they do not cooperate directly on the battlefield.

Assad hailed the deal and suggested he expected more backing from his strongest regional ally.

"We are confident that the Islamic Republic of Iran will support, with greater drive, just causes of nations and work for peace and stability in the region and the world," he said in a message to Iran's Supreme Leader Ayatollah Ali Khamenei.

In Iraq, veteran politician Hoshiyar Zebari, who has held ministerial office since the United States invaded Iraq and overthrew Saddam Hussein 12 years ago, said Baghdad had pushed hard for the accord which he said would have a positive impact.

"Any reduction of tension between Iran and the West, between Iran and the United States, would help the region," he said as the final elements of the deal were hammered out this week.

Iraq hosted one of the first face-to-face meetings in decades between U.S. and Iranian diplomats eight years ago, as well as a round of nuclear talks in 2013, and also carried messages between Tehran, New York and Washington, he said.

"We have a vested interest in this deal because we believe it will reduce tensions. Basically we don't want Iraq to be a score-settling ground between the United States and Iran," Zebari told Reuters.

RIVALS FOR INFLUENCE

Although the nuclear accord addresses a longstanding and central dispute, deep differences remain including over the extent of Iranian and U.S. power across the Middle East.

Those divisions mean that any political goodwill generated by the nuclear deal will be hard to translate into other areas, including resolving conflict in Syria and Iraq.

A U.S.-led coalition has waged air strikes across northern and western Iraq for nearly a year in support of ground forces trying to recapture territory from Islamic State.

The air support has been limited because the most effective forces fighting the hardline Sunni militants are Shi'ite militias, many of them directly supported by Iran.

Ayham Kamel, an analyst at Eurasia Group consultancy, said it was almost inconceivable that the nuclear deal would lead to direct coordination between Washington and Tehran in Iraq.

Iran's military support for Iraqi factions was in the hands of the Revolutionary Guards, he said. The Guards have sought to project Iranian influence abroad since Iran's 1979 Islamic Revolution.

"Its leaders will not move forward with anything substantive," Kamel said. "On the policy side perhaps the agreement will alleviate some sensitivities but the U.S. strategy in Iraq contradicts Iran's on several levels. A nuclear deal will not change that."

A senior Western diplomat in Baghdad also played down prospects of dramatic change, saying recent months had shown that the United States and Iran could pursue military strategies in Iraq in parallel without having to work together directly.

"What they need to do is de-conflict operations, as they did near the Iranian border," he said, referring to an apparent understanding which allowed Iranian jets to fly during a ground assault in Iraq's eastern Diyala province, which borders Iran.

If the nuclear deal leads Shi'ite Iran to be more assertive, Iraq's Sunni minority, which already complains of being marginalised by the Shi'ite-led government in Baghad, could feel more threatened.

Former prime minister Ayad Allawi, a secular Shi'ite allied with Sunni parties, gave a cautious welcome to the deal but said the talks should have included regional security as well.

"Regional security includes not interfering in internal affairs of countries," he said, pointing to Iran's deep military and political involvement in Iraq. "Unfortunately this matter has been ignored, yet it remains an important topic."

SYRIAN REBEL FEARS

In Syria, Washington's differences with Tehran run far deeper. Although both sides oppose the Islamic State militants who control much of the east of the country, their dispute over whether Assad should stay as president appears unbridgeable.

With the nuclear talks now concluded, diplomats from all sides may refocus on the Syria conflict - at least with a goal to de-escalate the fighting even if they cannot agree the way forward to a political settlement.

The spokesman for an alliance of rebel groups fighting Assad in southern Syria said Iran was backing him with "all its force", and said he was worried U.S. pressure would be inadequate to stop Iranian intervention.

Another rebel fighter in the north of the country said the agreement was a dangerous development. "Our fears from this agreement are an increase in Iranian influence in the region and this is what is making Assad happy," said Iyad Shamse.

But although the sanctions relief won by Iran through the nuclear deal gives it access to more money to support Assad, that money might only have a limited impact, said Noah Bonsey, senior analyst with International Crisis Group.

Assad's military power was gradually eroding and the cost of Iran's efforts to fill the gap would continue to rise, he said. "Even with more money at its disposal, the sustainability of Iran's investment in Assad rule is uncertain."

(By Dominic EvansAdditional reporting by Saif Hameed in Baghdad, Tom Perry and Sylvia Westall in Beirut)