Syria was expected to be one of the top agenda issues for President Vladimir Putin when he traveled to Tehran, the Russian President’s first visit in eight years and the first since Hassan Rouhani became the president of Iran. Tehran is naturally uncomfortable. Syria was becoming their fiefdom. They invested a lot in terms of lives and money and now a bigger fish [Russia] has come to Syria. Russia is seeking to cement the countries’ recent partnership in Syria even as the U.S. seeks to drive a wedge between them over the future of the Assad regime.

Putin met for more than 90 minutes Monday with Iran’s supreme leader, Ayatollah Ali Khamenei. Kremlin spokesman Dmitry Peskov said the Russian president brought the Ayatollah a copy of an old handwritten Quran which returns to the Umayyad era.

Pro-Iranian media channels in Syria and Lebanon hailed Mr. Putin’s visit as a “meeting of the titans.” Both men criticized the U.S. and other Western nations for insisting that any political solution in Syria should exclude Syrian President Bashar Assad.

“No one can or should force any form of government upon the Syrian people from the outside, or decide who should rule them,” he also added “This should be decided only by the Syrian people.”

Mr. Putin said in remarks shown on Russian television.

Ayatollah Ali Khamenei defended President Assad directly. “The Syrian president has gained the majority vote of the Syrian people with different political, religious and tribal views, and the U.S. doesn’t have the right to ignore this vote and election,” Khamenei said, according to Iran’s official IRNA news agency.

What is the core dispute between Russia and Iran regarding Syria?

The core of the dispute between Russia and Iran on Syria is because Moscow wants to establish relations with moderate Syrian opposition groups like Free Syrian Army [FSA], Iran does not agree with Russia on this act. Iranian officials are not willing to co-operate with the Syrian opposition because it sees them as terrorists and it will not accept to see them sharing the power with the Assad regime in Damascus.

Iran see Russia’s meeting with FSA leaders as a deviation from the previous position of Russia which they all always considered that all opposition armed factions as terrorist organizations, Russians fear that their military they might sink in an endless war in Syria so the Russian officials believe that they must also co-operate with United States and Arab countries to find a solution to the Syrian war according to the Russian interest and not the Iranian interest. Iranians are willing to continue fighting to keep Assad regime in power and to defeat the Syrian opposition until the change the balance to Assad’s favour. FSA brigades released a statement later refusing to meet with Russian officials .

The Iranian strategy in Syria since the beginning of the war was to end it in a military solution to keep the supply route to Hezbollah in Lebanon running and to main the Iranian religious and financial interests, which is the reason why Iran was not in favour of any political solutions to end the Syrian war. Iran’s interest requires that Assad regime should control Damascus and the Syrian coast, Hama and some parts of Quneitra, this the Iranian vision for the future of Syria.

Tehran is more committed to President Assad staying in power long term, because he allowed Iran to use western Syria to arm its military proxies in Lebanon. The Russians want to preserve access for their navy to the Mediterranean port of Tartus. And Syria has been Moscow’s main lever for influence in the Middle East and a willing buyer for its weapons. Putin has argued that the best way to fight terrorism in Syria is to back up Assad regime forces and preserve what’s left of the country’s government institutions.

Is it short lived alliance?

Views differ on the balance of interests between Moscow and Tehran including over their respective faithfulness to the Assad regime. A power struggle over the future of an Iranian-nurtured pro-government militia in Syria the National Defence Force, is one harbinger of potential tensions, which are eagerly picked up by western governments hoping to drive a wedge into an alliance perceived as hindering a political solution in Syria.

Moscow had “discussed the idea” of making the NDF part of President Assad’s government forces a military establishment with traditionally more attracted to Russia. Much depends on how the plan would be implemented, But the NDF issue points to the broader tussle with Tehran, which sees the militia established three years ago with the support of Iranian forces and its Lebanese proxy militant group Hezbollah as one of its main forces of influence over the war in the Syrian war.

Some tensions are already started publicly. Dmitry Rogozin, Russia’s deputy prime minister, called for greater efforts to build relations with Iran. “You can’t exactly say that all political forces in Iran fully share the view that Russia should become a strategic partner. Therefore we still have to do some serious work on that,” he said on television.

Russia’s intervention in Syria, both politically and geographically, are more aligned with the core, secular base of the regime and institutions such as the military. Their strategic interests run up the western coast, from the Russian naval base in Tartus through the Alawite heartlands to Latakia, from where Russia now flies its air strikes on Syria’s armed opposition and radical Islamist fighters.

Iran’s primary interests are in the south and central of Syria, particularly the supply route linking Hezbollah in Lebanon to Tehran. Rather than the state institutions, their focus has been on building the NDF and other Shiite militia groups.

General Mohammed Ali Jafari, commander of Iran’s Islamic Revolutionary Guards Corps, raised eyebrows this month when he said Russia had become militarily involved in Syria to serve its own interests, and “may not care if Assad stays as we do”.

But Moscow strongly dismisses talk of a split on this count. Sergei Lavrov, the Russian foreign minister, repeatedly stressed that Russia’s stance on President Assad had not changed and gave warning against further western attempts to make his departure a condition for a political process.

“Statements like that of Gen Jafari are a minority opinion, and those Iranian politicians who are determining the Iranian policy vector are completely in line with Moscow on the issue of Mr Assad,” said Nikolay Kozhanov, a former Russian diplomat at the embassy in Tehran.

Moscow is strongly aware that Iran may be on a long-term political trajectory towards the west a concern that became especially acute with the conclusion of the deal on Tehran’s nuclear programme this year. The two countries may very well drift further apart in the future. But for now, Syria is the hook that links them together.