Russia launched a fleet of bombers bound for Syria on Tuesday from an Iranian air base, becoming the first foreign military to operate from Iran’s soil since at least World War II.
Russian use of the base, with Iran’s obvious support, appeared to set back or at least further complicate Russia’s troubled relations with the United States, which has been working with Russia over how to end the Syria conflict.
It was the first time Russia has used the territory of another nation, apart from Syria itself, to launch such strikes since the Kremlin launched a bombing campaign to support Syrian President Bashar al-Assad in September last year.
The Iranian deployment will boost Russia’s image as a central player in the Middle East and allow the Russian air force to cut flight times and increase bombing payloads.
The head of Iran’s National Security Council was quoted by state news agency IRNA as saying Tehran and Moscow were now sharing facilities.
Both countries back Assad. Russia, after a delay, has supplied Iran with its S-300 missile air defense system, evidence of a growing partnership that has helped turn the tide in Syria’s civil war and is testing U.S. influence in the Middle East.
Relations between Tehran and Moscow have grown warmer since Iran reached agreement last year with global powers to curb its nuclear program in return for the lifting of U.N., EU and U.S. financial sanctions.
President Vladimir Putin visited in November and the two countries regularly discuss military planning for Syria. Iran has provided ground forces that work with local allies while Russia provides air power.
The United States said it was still assessing the extent of Russian-Iranian cooperation but described the new development as “unfortunate”.
State Department spokesman Mark Toner said the United States was looking into whether the move violated UN Security Council resolution 2231, which prohibits the supply, sale and transfer of combat aircraft to Iran.
Yet the sense of sovereignty runs so deep in Iranian culture that American efforts to have a bigger presence there were repeatedly rebuffed. Mr. Limbert, who as a young Foreign Service officer was one of the Americans taken hostage in 1979 at the embassy in Tehran, speculated that Russia was paying handsomely for the privilege. In Iran today, he said, the prospect of gaining revenue “can create a lot of flexibility.”
The bombers — too big for the air base Russia established in Syria in September — had been flying missions from Russia, a trip that will now be 1,000 miles shorter, officials said. Because they are based so much closer to the Syrian battlefields, the planes will be able to carry heavier payloads, adding new muscle to the recently faltering Syrian government effort in Aleppo.
Indeed, observers on the ground in Aleppo described a particularly heavy day of bombing, even if they could not identify the bombers. Civilians bore the brunt of the strikes. “The bombing today was intensive and massive,” said Mohamed al-Ahmed, a radiologist in an Aleppo hospital reached via the messaging app Viber, who said he had counted 28 victims.
Beyond any tactical advantages, launching Russian bombers from Iran also seemed to be part of a grander plan by President Vladimir V. Putin to cobble together a coalition to fight in Syria with Russia at its center. The use of the Iranian base comes on the heels of Mr. Putin’s recent détente with Turkey and amid Russian-American talks on cooperating more in the fight against the Islamic State in Syria.
“I think what Russia is trying to do is put together a broader coalition that goes beyond Russian-Iranian cooperation,” said Andrey V. Kortunov, the director general of the Russian International Affairs Council. “They consider this operation as another bargaining chip in their negotiations with the West.”
The new level of Russian-Iranian cooperation raises questions about whether the United States made a larger strategic error when, in choosing not to create “safe zones” or conduct major air operations over Syria, it left a window for the Russians to enter the war. President Obama warned in October that Moscow would be sucked into a “quagmire” as it sought to prop up Syria’s president, Bashar al-Assad.
Mr. Toner, the State Department deputy spokesman, said the Russian activity could violate a United Nations Security Council resolution that, he said, “prohibits the supply, sale and transfer of combat aircraft to Iran unless approved in advance by the U.N. Security Council.”
But it is not clear how that resolution would apply to combat aircraft flown by Russian pilots and not “transferred” to Iran. Mr. Toner said. “I just don’t have a definitive answer. I know our lawyers are looking at this.”
Mr. Assad’s position, dire when Russia entered the fray, was greatly strengthened, though his forces have faltered lately, one reason for basing Russia’s bombers closer. More important, the Russian entry has greatly limited American options.
Now, any American-led air operation would have to be coordinated with Russia to avoid conflicts over airspace, and the Pentagon has been highly suspicious of such coordination. An effort by Secretary of State John Kerry to work out some kind of enhanced cooperation — to fight the Islamic State and to provide humanitarian access to besieged cities has failed to produce results.
On Monday, Sergei Shoigu, the Russian defense minister, said that Moscow and Washington were coming closer to an agreement on Syria that would let the two sides fight together. Moscow has felt pressure to reach a political settlement as the humanitarian situation has deteriorated in Aleppo and Syrian government forces have had a series of setbacks there and in Latakia.
The new arrangement seems to have brought Tehran and Moscow into greater accord on Mr. Assad, who has not had absolute support from Russia. “The Iranians have been all in on Assad, and I think the Russians have now moved in that direction,” said Cliff Kupchan, a specialist on Russia and Iran at the Eurasia Group, a political analysis firm in Washington.
The new flights help solidify Russia’s presence in the Middle East, where its roster of allies has dwindled since the collapse of the Soviet Union. Russia “now views Iran as a powerful ally in the region and a stable source of income for its state industries,” said Konstantin von Eggert, a political analyst and commentator on Dozhd, a Russian independent television channel. “Tehran is a rich anti-American regime in a strategic region important to U.S. interests. What could be better for Putin?”
Ostensibly sent to fight terrorist groups, Russian forces in the air, joined by Iran and the Shiite militant group Hezbollah on the ground, have largely concentrated on shoring up government forces and punishing rebel groups, some supported by the United States.
But even with that assistance, the Syrian forces have been losing ground in Aleppo recently, highlighting the limits of an aerial bombing strategy to support a weary government army and its foreign allies. “In military terms, the situation around Aleppo is quite difficult, so there is a need to make the strikes much stronger,” said Aleksei Arbatov, an analyst at the Carnegie Moscow Center. “This decision constitutes a sharp intensification of our operation.”
Underscoring the government’s weakness, the Islamic State recently swatted away a heavily heralded attack by Syrian forces on Raqqa, the militant group’s de facto capital.
The statement from the Russian Defense Ministry said that Tupolev Tu-22MS bombers and Sukhoi-34 fighter-bombers took off from the base at Hamadan to strike targets in Syria in the provinces of Aleppo, Idlib and Deir al-Zour. It said the planes bombed Islamic State facilities as well as those controlled by Fath al-Sham, the Qaeda-affiliated group formerly known as the Nusra Front.
The Defense Ministry said the bombers hit arms depots, a training camp and three command-and-control points and killed numerous militants.
Also on Tuesday, Russia held naval drills in the eastern Mediterranean and Caspian Seas with ships equipped with the same type of Kalibr cruise missiles used to strike Syria when the Russian operation began last fall.
Adm. Vladimir Komoyedov, the head of the defense and security committee in Russia’s Parliament, said that deploying from the Iranian air base would save on costs, a crucial advantage as Russia drags through a long recession.
“The matter of warfare expenditures is at the top of the agenda today,” he was quoted as saying by the Interfax news agency.
It is not clear how the Russian-Iranian agreement was negotiated, but there was no denying the historic, and somewhat ironic, nature of the agreement.
“The irony is that the revolutionaries denounced the shah as a foreign puppet,” said Mr. Limbert, now a professor at the United States Naval Academy at Annapolis. “But these guys have done something that the shah never did.”