Vladimir Putin in Tehran for talks with leaders of Iran, Turkey

Russian President Vladimir Putin arrived Tuesday in Iran for a visit intended to deepen ties with regional heavyweights as part of Moscow's challenge to the United States and Europe amid its grinding campaign in Ukraine.

In only his second trip abroad since Russian tanks rolled into its neighbour in February, Putin is meeting Iran's President Ebrahim Raisi and Turkish President Recep Tayyip Erdogan on pressing issues facing the region, including the conflict in Syria and a UN-backed proposal to resume exports of Ukrainian grain to ease the global food crisis.

As the West heaps sanctions on Russia and the costly campaign drags on, Putin is seeking to bolster ties with Tehran, a fellow target of severe US sanctions and a potential military and trade partner. In recent weeks, Russian officials visited an airfield in central Iran at least twice to review Tehran's weapons-capable drones for possible use in Ukraine, the White House has alleged.

Iran rolled out a long red carpet for Putin at Tehran's Mehrabad airport, where Iranian Oil Minister Javad Owji greeted him warmly before he was whisked into his presidential convoy to the city.

But perhaps most crucially, the Tehran trip offers Putin a chance for a high-stakes meeting with Erdogan, who has sought to help broker talks on a peaceful settlement of the Russia-Ukraine conflict, as well as help negotiations to unblock Ukrainian grain through the Black Sea.

Turkey, a NATO member, has found itself opposite Russia in bloody conflicts in Azerbaijan, Libya and Syria. It has even sold lethal drones that Ukrainian forces have used to attack Russian troops. But Turkey hasn't imposed sanctions on the Kremlin, making it a sorely needed partner for Moscow. Grappling with runaway inflation and a rapidly depreciating currency, Turkey also relies on the Russian market.

The gathering has symbolic meaning for Putin's domestic audience as well, showing off Russia's international clout even as it grows increasingly isolated and plunges deeper into confrontation with the West. It comes just days after US President Joe Biden's visited Israel and Saudi Arabia — Tehran's primary rivals.

From Jerusalem and Jeddah, Biden urged Israel and Arab countries to push back on Russian, Chinese and Iranian influence that has expanded with the perception of America's retreat from the region.

It was a tough sell. Israel maintains good relations with Putin, a necessity given Russian presence in Syria, Israel's northeastern neighbour and frequent target of its airstrikes. Saudi Arabia and the United Arab Emirates have declined to pump more oil beyond a plan approved by their energy alliance with Moscow.

But all the countries - despite their long-standing rivalries — could agree on drawing closer to counter Iran, which has rapidly advanced its nuclear program since former US President Donald Trump abandoned Tehran's atomic accord with world powers and reimposed crushing sanctions. Talks to restore the deal have hit a deadlock.

Backed into a corner by the West and its regional rivals, the Iranian government is ramping up uranium enrichment, cracking down on dissent and grabbing headlines with optimistic, hard-line stances intended to keep the Iranian currency, the rial, from crashing. Without sanctions relief in sight, Iran's tactical partnership with Russia has become one of survival, even as Moscow appears to be undercutting Tehran in the black market oil trade.

“Iran is (the) center of dynamic diplomacy,” Iranian Foreign Minister Hossein Amirabdollahian wrote on Twitter, adding the meetings will “develop economic cooperation, focus on security of the region ... and ensure food security.” Fadahossein Maleki, a member of the Iranian parliament's influential committee on national security and foreign policy, described Russia as Iran's “most strategic partner” on Monday. His comments belied decades of animosity stemming from Russia's occupation of Iran during World War II — and its refusal to leave afterward.

After his arrival, Putin held talks with Raisi that followed meetings in Moscow in January and again last month in Turkmenistan. During his fifth visit to Tehran, Putin will also meet Iran's Supreme Leader Ayatollah Ali Khamenei to continue what Kremlin foreign affairs adviser Yuri Ushakov called a “trusting dialogue.” “Our relations are developing at a good pace,” Putin said at the start of the meeting with Raisi, noting that Moscow and Tehran “strengthen their cooperation on international security and contribute significantly to the Syrian settlement.” Raisi voiced hope that Putin's visit will help expand cooperation on regional and international issues.

The focus of later trilateral talks among the presidents will be the decade-old conflict in Syria, where Iran and Russia have backed President Bashar Assad's government, while Turkey has supported armed opposition factions. Russia intervened in the conflict in 2015, pooling efforts with Iranian forces and using its air power to shore up Assad's fledgling military.

Ushakov said the parties will discuss efforts to encourage a political settlement, while Erdogan is expected to take up Turkey's threats of a new military offensive in northern Syria to drive away US-backed Syrian Kurdish fighters from its borders. The operation is part of Turkey's plan to create a safe zone along its border with Syria that would encourage the voluntary return of Syrian refugees.

In a meeting with Erdogan, Khamenei delivered a stern warning against the planned Turkish incursion.

"Any sort of military attack in northern Syria will definitely harm Turkey, Syria and the entire region, and will benefit terrorists," Iran's top leader said, stressing the need to “bring the issue to an end through talks.” 

Iran and Turkey signed preliminary agreements covering investment, diplomacy, media and business, among other fields, and pledged to triple bilateral trade, to $30 billion.

In his speech, Erdogan called for solidarity in the fight against Kurdish militant groups as well as a network led by a U.S.-based Muslim cleric whom Ankara accuses of orchestrating a failed coup in 2016.

Talks to lift a Russian blockade and get Ukraine's grain into global markets also are on the agenda. Last week, UN, Russian, Ukrainian and Turkish officials reached a tentative agreement on some aspects of a deal to ensure the export of 22 million tons of desperately needed grain and other agricultural products trapped in Ukraine's Black Sea ports by the fighting.

Tuesday's meeting between Putin and Erdogan could help clear remaining hurdles, a major step toward alleviating a food crisis that has sent prices of vital commodities like wheat and barley soaring.