Syrian allies Iran and Russia are working together to prevent a Western military attack on Syria, the Iranian president said, as Russia said it is sending warships to the Mediterranean, where U.S. ships are already in position.
Both Iran and Russia would work in "extensive cooperation" to prevent any military action against Syria, Iranian President Hassan Rouhani said in statements carried by several Iranian state-controlled media outlets. Western military action against Syria would be an "open violation" of international laws, he said.
"Military action will bring great costs for the region," Rouhani said, and "it is necessary to apply all efforts to prevent it."
Gen. Mohammad Ali Jafari, chief of Iran's powerful Revolutionary Guards, told the Tasnim news website, that an attack on Syria "means the immediate destruction of Israel."
The statements came as Russian state-owned media reported that two Russian warships were sailing for the eastern Mediterranean Sea to protect Russian interests as tensions escalate in the region.
The ships, a missile cruiser and a large anti-submarine vessel, are traveling from the North Atlantic and will arrive in a number of days, Reuters reported.
Middle East analysts say weapons and terrorist networks at Iran's disposal mean the threats should be taken seriously.
"Iran is a huge threat," said Ariel Cohen, a senior research fellow at the Heritage Foundation.
Both Iran and Syria have threatened to retaliate against Israel and other U.S. allies in the Middle East in the event of a U.S. attack on Syria over its alleged use of chemical weapons against civilians. Hundreds of Syrians in a region held by rebels were reported killed in an Aug. 21 attack.
Iran's ruling mullahs are Syria's main ally in the region and view the survival of the Assad regime as important to their aims. Mehdi Taeb, confidant of Supreme Leader Ali Khamenei, said Syria is Iran's "35th province. ... If we lose Syria we won't be able to hold Tehran," writes Karim Sadjapour, an Iran expert at the Carnegie Endowment for International Peace.
Syria provides Iran a port on the Mediterranean Sea and a transit to Iran's terrorist proxy in Lebanon, Hezbollah. Iran is suspected of helping Syria evade U.S. and European sanctions by selling its oil on the international market, according to a report from Reuters. Iranian military leaders view an attack to topple Syria's Assad regime as an opening salvo in a Western campaign to topple their own regime in Iran, Sadjapour said.
Iran could order its Islamic Revolutionary Guard Corps or Hezbollah to use their networks around the world to target countries that support the military strike.
Iran could also try to close the Strait of Hormuz, the narrow Persian Gulf passage for about 20% of the world's petroleum supply, said Cohen of the Heritage Foundation.
"When we keep an eye on Syria we need to keep an eye on the security of shipping, especially the shipping of oil in the straits," Cohen said.
During the Iran-Iraq War of the 1980s, both countries targeted oil tankers carrying their adversary's oil. Iran now has multiple military platforms it can use to threaten maritime traffic in the Gulf, including hard-to-detect mini-submarines and small, high-speed patrol boats that can swarm a carrier task force.
U.S. forces in the region are prepared for such attacks but would not be able to prevent them all right away, said Chris Harmer, an analyst at the Institute for the Study of War who worked on military plans for the Persian Gulf as a commander in the Navy.
Recent experience, however, shows that Iranian weapons still pose a threat to modern navies.
During Israel's 2006 war with Hezbollah, the Iran-backed militia nearly sunk the Israeli corvair Hanit with an advanced sea-skimming missile that crippled the ship's propulsion system and killed four sailors.
Hezbollah, which relies on Syria as a transit point for weaopns and other aid from Iran, also has thousands of rockets hidden in its base in southern Lebanon that it can launch at Israeli cities. And Syria has missiles it can launch at Saudi Arabia, Jordan, Turkey, Cyprus and Israel.
Then there is terrorism and political unrest, a staple of Middle East violence.
Iran, a Shiite Muslim theocracy, could spur uprisings among Shiite populations in Sunni-led Gulf countries, especially Bahrain, which has a Shiite majority, and Saudi Arabia and Kuwait, which have considerable Shiite minorities, Cohen said.
It could also activate Hezbollah and the Revolutionary Guards throughout the Middle East and the world to hit U.S. or European civilian or military targets. It has done so before.
Bulgarian prosecutors have tied the 2010 bus bombing that killed six Israeli tourists to a Hezbollah cell, which Israel said was linked to Iran, charges that both Hezbollah and Iran deny.
Argentine prosecutors say Iran-backed Hezbollah terrorists were behind the bombings in 1992 and 1994 against Israeli and Jewish targets that killed a combined 116 people in Buenos Aires.
And Hezbollah killed a combined 457 American and French troops and Lebanese civilians in three bombings in Beirut in 1983 according to France and the USA.
Some analysts say Iran's current leadership is unlikely to retaliate.
Analyst Harmer said the Syrian threats are a bluff.
"The Syrian Arab Army can't beat a ragtag, ill funded, poorly equipped, barely trained insurgency, what exactly are they going to do against the most powerful military in the world?" Harmer said.
And while Iran may want to retaliate, it usually does so through Hezbollah, which "is task saturated between helping Assad stay in power, and protecting Shia neighborhoods in Beirut from retaliatory car bombs," he said. "I don't think Iran can run the risk of retaliating on their own."
Suzanne Maloney, an Iran expert at the Brookings Institution's Saban Center for Middle East Policy and a former policy planner at the State Department under George W. Bush, said the public statements of Iran's new president, Hassan Rouhani, show that he "wants to get out of this thing with limited damage to Iran's reputation."
"He clearly understands that if Iran gets into a shooting war with the United States, Europe and international intervention, it's likely to be a quicker path to regime elimination than any other."