Iran President Hassan Rouhani shakes hands with Russian President Vladimir Putin prior to attending the Gas Exporting Countries Forum, GECF, summit meeting in Tehran, Iran, Monday, Nov. 23, 2015.

Russia and Iran have “unity of views” on Syria, a spokesman for the Kremlin said Monday after President Vladimir Putin held talks in Tehran with supreme leader Ayatollah Ali Khamenei.

Describing the meeting as “quite constructive”, the spokesman said Iran and Russia were against “external attempts to dictate scenarios of political settlement in Syria” and any change in leadership should come through elections.

The visit comes as Russia, the United States, France and others are talking about possible joint action against the Islamic State of Iraq and Syria (ISIS) group following the terror attacks in Paris and the downing of a Russian passenger jet in Egypt. Putin’s trip also comes on the heels of agreement on an incomplete peace plan that calls for talks between Assad and his foes.

Moscow and Tehran have been the key backers of Syrian President Bashar Assad throughout his nation’s civil war, which has killed over 250,000 people and turned millions into refugees.

Russia has shielded Syria from international sanctions, and on Sept. 30 it launched an air campaign against ISIS and other insurgents, while Tehran has sent military advisers to shore up Assad.

The peace plan put forward by 17 nations a day after the Paris terror attacks sets a Jan. 1 deadline for the start of negotiations between Assad and the opposition.

The proposal, which seems to draw heavily on a recently circulated Russian initiative, states that “free and fair elections” would be held according to a new constitution within 18 months. To clarify the timeline, the State Department said last week that the clock starts once Assad’s representatives and opposition figures begin talks on a constitution. The vote would determine a new parliament, though not necessarily a new president.

The plan says nothing about Assad’s fate, and does not say which of Syria’s many opposition factions would take part in the negotiations.

Russia and Iran both have bristled at demands for Assad to step down, saying his future must be decided by the Syrians as part of the peace process. But some have speculated that Moscow could be prepared to see Assad phased out of power as part of a deal that would guarantee stability in Syria and protect Russia’s interests there. Tehran is widely seen as taking a more rigid stance.

Shiite Iran has staunchly backed Assad, who belongs to Syria’s Alawite minority, an offshoot of Shiite Islam, seeing him as a bulwark against its archrival, Saudi Arabia, and other Sunni monarchies of the Gulf. Tehran has sent more advisers to Syria in recent weeks, reportedly including Gen. Qassem Soleimani, who heads the elite Quds Force of the Revolutionary Guard. Iran says it has sent advisers but no combat forces.

Taking advantage of the Russian airstrikes, the Iranians and Hezbollah have spearheaded the ongoing Syrian offensive intended to win back some ground after a string of losses earlier this year. Moscow has closely coordinated its air campaign with Tehran, with Russian warplanes flying over Iran and Iraq to avoid the airspace of Turkey and other NATO members.

Iran’s ambassador to Russia said on Monday that Moscow had started the procedure of supplying Tehran with S-300 anti-missile rocket system, according to the Tasnim news agency.

Russia and Iran signed a contract for Moscow to supply Tehran with S-300 surface-to-air missile systems on Nov. 9.

“Iran and Russia signed a new contract and the procedure of delivery of S-300 has started,” Iran’s Ambassador to Russian Mehdi Sanaei was quoted as saying by Tasnim.

Related articles across the web

• Iran's "Line of Hezbollah" is Khamenei's new official publication
• Supreme Leader Revives Feared Intelligence Unit Of Iran's IRGC
• Khamenei slams Israel over al-Aqsa mosque violence
• Russia is coordinated with Iran on Syria
• More than 700 dead in horror stampede
• Yom Kippur Provides No Respite From Iranian Rhetoric Against Israel
• Iran leader: Saudi govt responsible for haj "catastrophe"
• Putin's Play in Syria - Bloomberg View
• Russia is coordinated with Iran on Syria
• Iran's Supreme Leader sharpens his revolutionary message through a new publication