This US base in Syria is a huge thorn in Russia and Iran's side - but they can't do much more than complain about it
- Moscow, Tehran and the Syrian regime have repeatedly accused the US of training ISIS fighters at the al-Tanf garrison, but all they've been able to do is complain about it.
- In reality, the base disrupts the flow of weapons from Iraq to Damascus.
- It also has served as a training ground for Syrian rebels fighting Damascus, which US analysts say are not terrorists.
Russia and the Syrian regime warned the US in early September that they planned to carry out counterterrorism operations near a key US garrison in southeastern Syria known as al-Tanf, where several hundred Marines have been stationed since at least 2016.
But the US responded with a live-fire exercise, and the Russians backed down.
In fact, the al-Tanf garrison has long drawn the ire of Moscow, Tehran and the Syrian regime - but all they've been able to do is complain about it.
The US is "gathering the remnants of the Islamic State at this base in order to later send them wage war on the Syrian army," Syrian Foreign Minister Walid Muallem said in late September, according to Sputnik, a Russian state-owned media outlet.
"According to satellite and other surveillance data, terrorist squads are stationed [at al-Tanf]," Russian General Valery Gerasimov told Russia's Pravda in late 2017. "[Terrorists] are effectively training there."
Iran's Press TV also cited Gerasimov's quote a June 2018 article titled, "US forces training terrorists at 19 camps inside Syria: Russian expert."
Without any real evidence, US adversaries have lobbed many rhetorical attacks against the US forces for supposedly harboring or training terrorists at al-Tanf.
Damascus and Russian state-owned media even claimed in June that the US was preparing a "false flag" chemical attack "identical to the kind that took place in Douma" at al-Tanf.
"The U.S. led Coalition is here to defeat ISIS, first and foremost, and that is the objective of the presence in at al-Tanf," US Army Colonel Sean Ryan, a spokesman for Operation Inherent Resolve, told Business Insider in an email.
"No U.S. troops have trained ISIS and that is just incorrect and misinformation, it is truly amazing some people think that," Ryan said.
The US has trained Syrian rebels at al-Tanf, namely a group called Maghawir al Thawra, which "is fairly secular by regional standards and has been at the forefront of the fight against ISIS," Omar Lamrani, a senior military analyst at Stratfor, told Business Insider.
But the "claim that the US is training ISIS and like-minded groups at al Tanf is certainly absurd," Lamrani said.
"To the Russians and Iranians, almost any group fighting against the Syrian government can be labeled a terrorist group," Lamrani said.
So why do Russia, Iran and the Syrian regime care so much about this garrison?
"I'd say that the primary reasons why Iran cares about it so much is, again, it blocks the Bagdhad-Damascus highway," Lamrani said, which Tehran uses to transport weapons to Damascus, where the Syrian regime is based.
"The reason they want the land route is that it's easier to bring [weapons] across land in greater quantities, and the shipping route is very vulnerable to Israeli interception, and the air route is expensive and often gets hit by Israeli airstrikes," Lamrani added.
Moscow, on the other hand, is upset about al-Tanf because "it's the last area in Syria where the United States is involved with rebels on the ground that are not Syrian Democratic Forces," Lamrani said.
The Russians and Syrian regime have "open channels" with the SDF, and want to negotiate - not fight - with them, Lamrani added.
But Moscow, Tehran and the Syrian regime's ire might go beyond just styming the flow of weapons to Damascus and training rebels.
"There's a history at that garrison at al-Tanf," Max Markusen, associate director and an associate fellow of the Transnational Threats Project at CSIS, told Business Insider.
"I think that the Syrian regime, the Russians and Iranians, would see it as a [symbolic] victory if the United States pulled out of there than just sort of tactical level objectives," Markusen said, adding that there's much resentment for the US having trained rebels at al-Tanf too.
But they're not foolish enough to kinetically force US troops out because "the costs of escalation are too high," Markusen said.
So they're relegated to discrediting the al-Tanf garrison.
Going forward, "we will continue to see an escalation of rhetoric," Markusen said, but "I don't there's going to be a major outbreak of conflict."