Russia denied Thursday it had a "hidden agenda" on Syria as it launched a fresh round of crisis diplomacy by hosting the Iranian and Syrian foreign ministers ahead of peace talks in Switzerland.
Iranian Foreign Minister Mohammad Javad Zarif arrived in the Russian capital late Wednesday on the same jet as Syrian Foreign Minister Walid Muallem.
Zarif met Lavrov on Thursday and the Russian foreign minister was due to hold talks with Muallem separately on Friday. The three sides are working to come up with a joint stance that would keep Syrian President Bashar al-Assad in power after next week's talks.
Iran's ambassador to Moscow, Mehdi Sanaie, told the Interfax news agency that the three diplomats would meet for joint talks later in the day.
"This does not mean that we have some tri-party (peace) draft," Lavrov told reporters after his talks with Zarif.
"We have nothing to hide," said Lavrov. "We have no hidden agenda."
Zarif will also meet later on Thursday with Russian President Vladimir Putin to discuss curbs on Tehran's nuclear programme and the possible purchase of missiles that could fend off punitive strikes by arch-foe Israel.
The talks between the Damascus regime and its two main allies come four days after a "Friends of Syria" meeting in Paris of mainly Western and Gulf nations backing the rebels.
World powers are seeking to bring the warring parties together for their first direct discussions at the so-called Geneva II peace talks beginning on January 22.
"There is a strong Tehran-Moscow-Damascus axis emerging," said Russian PIR Centre research institute analyst Andrei Baklitsky.
"Russia and Iran support Assad and a political settlement to the conflict -- and this is the only thing working right now," said the analyst.
"The West has no other alternative."
Millions have been displaced and at least 130,000 killed in nearly three years. Some 70 nations that gathered in Kuwait on Wednesday raised $2.4 billion for what aid organisations describe as the world's worst unfolding humanitarian disaster.
Putin has been on the ascendance ever since managing to avert seemingly inevitable US strikes against Russia's closest Middle East ally in September by forcing Assad to renounce his chemical arms.
Now Moscow wants to convince Washington to accept Tehran's presence at the Geneva conference in order to bolster its efforts to keep Assad in power and curb the future influence of his foes.
"We are proceeding on the premise that in any case, Iran should inevitably be a part of a set of measures to settle the Syrian problem," Lavrov said on Thursday.
Zarif said only that Iran would participate in the Swiss meetings "if we are invited".
But the Russian foreign ministry also stressed in a statement that the Syria meetings should be "based on the provisions of the (June 2012) Geneva Communique" -- a document Iran rejected because it paved the way for a transitional government that could potentially replace Assad.
The United States wants Iran to sign up to the accord before it can formally join the talks.
Analysts said Moscow and Tehran are now trying to draw up their own post-war plan that is based on Washington's growing anxiety about the presence of Al-Qaeda sympathisers in rebel ranks.
"A large part of these negotiations are focused on what happens after Geneva II," said Alexander Konovalov of Moscow's Institute for Strategic Assessment.
The Kremlin appears to hold strong leverage over the Islamic republic because of Iran's desire to purchase Russian missiles and other high-tech arms.
This can help Moscow wrest concessions sought by the West over Tehran's support for Hezbollah forces backing up Assad from Lebanon as well as its contested nuclear drive.
Iran has agreed to curb its nuclear programme starting January 20 in exchange for about $7 billion in sanctions relief.
Moscow in 2010 bowed to US and Israeli pressure by aborting an $800-million deal to supply Tehran with an S-300 surface-to-air missile system that would have imperilled any Israeli sorties aimed at Iranian nuclear sites.
But Iran's Fars news agency said a new Tehran delegation will shortly try and purchase missiles that could be worth even more money and include the more powerful Antey-2500 system.
Russia's Kommersant daily reported Thursday that talks with Zarif will also include a discussion of Russia's possible substantial oil purchases from Iran.
A Russian government source told the paper that Moscow is free to sign such a deal because it "never agreed to western sanctions".