DUBAI - On his first trip outside the former Soviet Union since the invasion of Ukraine, Russian President Vladimir Putin will arrive in Iran on Tuesday for a summit with his Iranian and Turkish counterparts on the Syrian conflict, Iranian state TV said.

The three countries are working together to try to reduce the violence in Syria despite supporting opposing sides in the war. Russia and Iran are Syrian President Bashar al-Assad’s strongest backers, while Turkey supports anti-Assad insurgents.

Turkey's President Tayyip Erdogan has threatened to launch another operation in Northern Syria, which Tehran and Moscow oppose. In Tehran, Putin and Erdogan will meet to discuss a deal aimed at resuming Ukraine's Black Sea grain exports.

The spectre of an emerging U.S.-backed Arab-Israeli bloc that could tilt the Middle East balance of power further away from Iran has accelerated its clerical rulers' efforts to strengthen strategic ties with the Kremlin.

"Considering the evolving geopolitical ties after the Ukraine war, the establishment tries to secure Moscow's support in Tehran's confrontation with Washington and its regional allies," said a senior Iranian official, who asked not to be named.

Sending a clear message to the West that Russia will seek to boost ties with anti-West Iran, Putin will meet the Islamic Republic's most powerful authority, Supreme Leader Ayatollah Ali Khamenei, just a few days after U.S. President Joe Biden visited Israel and Saudi Arabia.

Putin's visit to Tehran is watched closely as Russia's invasion of Ukraine has reconfigured the global oil market and because of Washington's warning about Tehran's plan to provide Russia with up to several hundred drones. Tehran has denied selling drones to Moscow to use in Ukraine.

Emboldened by high oil prices after the Ukraine war, Tehran is betting that with Russia's support it could pressure Washington to offer concessions for revival of a 2015 nuclear deal.

Under the deal, Tehran curbed its sensitive nuclear work in exchange for lifting international sanctions.

But former U.S. President Donald Trump exited the pact in 2018 and reimposed crippling sanctions on Iran. A year later, Tehran started violating nuclear limits of the pact.

Almost a year of indirect talks between Tehran and Washington in Vienna stalled in March, with Iran questioning the United States' resolve and Washington calling on Tehran to drop extra demands.

But Moscow and Tehran, both subject to U.S. sanctions, have overlapped interests. Iran, whose oil industry has struggled for years under U.S. sanctions, has long relied on Chinese oil purchases to keep the economy afloat. Since the start of Ukraine war, Moscow has taken away Iran's oil market in Asia.

In May, Reuters reported that Iran's crude exports to China have fallen sharply as Beijing favoured heavily discounted Russian barrels, leaving almost 40 million barrels of Iranian oil stored on tankers at sea in Asia and seeking buyers.

(Writing by Parisa Hafezi; Editing by Michael Perry)