Cairo/Riyadh: The election of a moderate Iranian president could help rein in hostility between Tehran and its Arab neighbours, but many Arabs doubt he can end a sectarian confrontation that has been inflamed by war in Syria.

Hassan Rouhani, a Shiite cleric known for a conciliatory approach and backed by reformists, will have only limited say in policy determined by Iran’s supreme leader; but with the Syrian carnage fuelling rage among Sunni Arabs across the region, any gestures from Tehran may help contain it.

“We hope the new Iranian president will be a believer in a political solution in Syria,” said one ambassador at the Arab League in Cairo.

“All that we read about Rouhani might be grounds for hope - but there is a great difference between election campaigns and what is said once in office.”

For the US and Western powers, at odds with Iran for decades and now rallying with arms behind rebels fighting Syria’s Iranian-backed president, fierce religious enmities in the oil-rich Middle East add to fears of wider instability.

In Syria, where mainly Sunni rebels are battling Iran’s ally President Bashar Al Assad and his Alawite establishment, who belong to an offshoot of Shi’ism, opposition activists saw little hope for change from Rouhani: “The election is cosmetic,” said Omar Al Hariri from Deraa, where the uprising began during the Arab Spring two years ago. Mohammad Al Hussaini, from the Sunni Islamist rebel group Ahrar Al Sham in Raqaa, noted power in Iran rested with Supreme Leader Ayatollah Ali Khamenei.

“The powers given to the Iranian president are weak these days,” he said. “They are fake powers.”

In Egypt, by far the biggest Arab nation, new rulers from the Muslim Brotherhood had lately launched a rapprochement with Iran but have now joined a Sunni call for jihad in Syria after Iran’s Lebanese ally Hezbollah sent in its fighters last month.

Traditionally more open than the Saudi clerical hierarchy to conciliation across the sectarian divide, the Brotherhood still hopes for a change of heart in Tehran: “We are looking forward to seeing how the winner is going to act,” said Murad Ali, a spokesman for the Islamist movement’s Freedom and Justice Party.

“Will there be any change to the policies from the Iranians, especially concerning the Syrian crisis? We are in general open to cooperation with Iran ... However, we do have our concerns ... related to ... their interference in Syrian affairs.”

On the streets of Cairo, however, sectarian passions are running high, piling pressure on Egyptian and other Arab rulers.

Outside the Al Azhar Mosque, built 1,000 years ago by the Shiite Fatimid caliphs who founded the city but now a major seat of Sunni learning, construction worker Mohammad Abdul Sattar, 35, said: “All Egyptians hate Iran after what has happened in Syria. What’s happening there now is Shiites killing Sunnis.”

Limousine driver Abdul Aziz Darwish, 57, had low expectations of any change in Tehran: “All Iranians are the same,” he said.

Standing by his fresh-juice stand, Khaled Fathi, 49, twinned his anger at Iranian involvement in Syria with suspicion of the welcome that Islamist President Mohammad Mursi gave earlier this year to Iran’s hardline outgoing president, Mahmoud Ahmadinejad: “Iran makes problems for us all over the world,” he said. “Iran is helping Mursi, I’m sure of it.”

A group of Lebanese Sunni clerics, visiting Al Azhar while attending the Cairo conference that has issued a call for holy war in Syria, voiced some hope for change from Rouhani, however: “Maybe this new president in Iran will be better,” said Shaikh Hassan Abdul Rahman from the city of Tripoli, which has seen recent fighting between Lebanese Sunnis and Shiites.

Shaikh Malek Al Jdeideh, also from Tripoli, said: “We came to Egypt to tell Mohammad Mursi that we reject Iranian actions in Syria ... But we are working for all religions to be at peace.”

Sectarian atrocities in Syria, and the open appearance of Iran’s Lebanese allies on the battlefield, has forged an unusual degree of unity among major Arab governments following the wave of revolt that shook the region and notably replaced US ally Hosni Mubarak in Egypt with the Islamists of the Brotherhood.