Iran's threat to the U.S. and its interests isn't just limited to their military might. The country has also built up a network of proxy groups to extend its influence across the region. First and foremost is Hezbollah in Lebanon.
Iran and Hezbollah have worked with each other since Hezbollah's earliest days — the main goal being to threaten Israel.
As for Syria itself, Iran has been propping up the Syrian government in its civil war with weapons, money, advisors and fighters. The majority of this happens through the air, but with the Syrian government regaining control over more territory, there's more ground access as well.
To prevent Iran from having unfettered access to Syria, the U.S. maintains a small presence on the Syria-Iraq border in a Syrian garrison known as al-Tanf. It sits on a major highway from Baghdad to Damascus.
Iran also provides weapons to militias in Iraq, though it's a little complicated here. That's because while the U.S. considers some of these groups Iranian proxies, the degree to which they align with Iran varies.
Some of these militias, known collectively as Iraq's Popular Mobilization Forces, are pro-Iraqi government while some are more closely aligned with Iran's forces. They're all also funded and recognized by Iraq's government.
Then there's Yemen, where Iran has been backing Houthi rebels in a civil war that's created one of the world's worst humanitarian crises. The U.S. and its allies have accused Iran of shipping arms to the Houthis through Houthi-controlled ports in Yemen.
So far, there's been no clear indication any of these groups have changed their posture toward the U.S. in a way that increases their threat.