Iran has vowed revenge on the US after Trump's airstrike killed its top military commander. Here's how it could do it.

(Photo by Majid Saeedi/Getty Images)

A protester holds up a burning photo of President Donald Trump outside the former US Embassy in Tehran, Iran, in November 2018.

• Qassem Soleimani, the leader of Iran's elite Quds Force, died in an airstrike ordered by President Donald Trump, the Department of Defense said in a Thursday night statement.
• Iran's leadership has vowed to exact revenge on the US for the death of a man they consider a hero.
• Though Iran is not as militarily strong as the US, it has - under Soleimani's leadership - developed a wide range of unconventional tools that could devastate the US.
• It could carry out cyber- and terror attacks on the US, as well as leverage its regional partners to attack US bases. Below is a list of what the Islamic republic could do.
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Iran's leadership has vowed to exact revenge on the US after an American airstrike, ordered by President Donald Trump, killed its most powerful and beloved military leader Qassem Soleimani.

Iranian Foreign Minister Mohammad Javad Zarif called the US action "international terrorism," while Supreme Leader Ayatollah Ali Khamenei warned that "harsh retaliation is waiting."

Multiple foreign-policy experts - including former US Special Envoy Brett McGurk, former national security adviser Ben Rhodes, and former White House Middle East and Gulf coordinator Robert Malley - have interpreted the airstrike as Trump effectively declaring war on Iran.

Though Iran is not as militarily strong as the US, it has - under Soleimani's leadership - developed a wide range of unconventional tools that could devastate the US. Here's how Iran could strike back.

(Office of the Iranian Supreme Leader via AP)

Revolutionary Guard Gen. Qassem Soleimani in Tehran in September 2016.

Attacks on US personnel across the Middle East

According to the Defense Department, Soleimani had been "actively developing plans to attack American diplomats and service members in Iraq and throughout the region." It said the airstrike was a "decisive defensive action to protect US personnel abroad."

Iran has now gained more momentum to attack US personnel in their region.

"Immediate challenges will include keeping our embassies, troops, and personnel safe in Iraq, Syria, Lebanon, and the Gulf," tweeted Dan Shapiro, who served as US Ambassador to Israel from 2011 to 2017.

Iraqi Security Media Cell via Reuters

Burning debris seen on a road near Baghdad International Airport, which Iraqi paramilitary groups say were caused by three rockets, on January 3, 2020.

Rocket barrages on Israel, Saudi Arabia, or the UAE

Another way Iran could attack the US is by unleashing a series of attacks on US or US-allied troops and military bases across the Middle East and Gulf region.

Iran's options for retaliation could "include a wave of rocket attacks on Israel, Saudi, possibly the UAE ... and a surge of ground attacks on troops and bases in the region," counterinsurgency expert David Kilcullen told The Daily Beast.

Kilcullen worked alongside former CIA Director David Petraeus on the US Iraq War troop surge from 2007 to 2008.

Cyber war, terror attacks, kidnapping

Iran could also unleash attacks in a "more asymmetric or unconventional style hits in Europe, Africa, South America and/or the continental US," Kilcullen told The Beast.

This could come in the form of cyberattacks - which Soleimani himself has threatened in the past - terror attacks, assassinations, or kidnappings.

Michael Gruber/Getty Images; Olivier Douliery-Pool/Getty Images; Samantha Lee/Business Insider

A graphic of Iranian President Hassan Rouhani and Trump.

Soleimani had a lot of friends who want to strike back

As leader of the Quds Force, the elite unit of Iran's Islamic Revolutionary Guard Corps, Soleimani fostered longstanding relationships and trained various militias around Middle East.

Some allies have already vowed to fight the US to venge Soleimani's assassination.

Here's a list of the Quds Force's partners across the Middle East:

• Shiite militias in Iraq, which have battled US forces in the country since their 2003 invasion. These groups include the Asaib Ahl al-Haq and Kataeb Hezbollah paramilitary groups, and the Badr Organization military wing, according to the Associated Press (AP).
• The Lebanon-based Hezbollah militia, which the Quds Force helped found in the 1980s. The group has been held responsible for numerous skirmishes in the region, and has tens of thousands of rocket that could easily strike US ally Israel. Hezbollah officials also occupy top posts in the current Lebanese government.
• The Shiite Houthi rebels in Yemen, where a Saudi-led alliance is waging a proxy war. Last September it claimed responsibility for attacks on Saudi Aramco's oil facilities in the kingdom last year. Saudi Arabia and the US blamed Iran for the attacks, which Iran denied.
• Hamas, the Sunni militant organization in the Gaza Strip. Though Iran stopped giving Hamas financial assistance in 2011, the country is believed to have continued military support to its armed wing, the AP reported.

amCharts/Business Insider

Map showing countries containing bases of Quds Force's regional partners.

Hezbollah's leader, Hassan Nasrallah, vowed in a Friday morning speech to "continue on the path" of Soleimani, and called on fighters around the world to punish those behind the attack.

"Meting out the appropriate punishment to these criminal assassins ... will be the responsibility and task of all resistance fighters worldwide," Nasrallah said, according to The Daily Telegraph.

Khalid al-Mousily/Reuters

Kataeb Hezbollah leader Abu Mahdi al-Muhandis in Baghdad, Iraq, on November 3, 2015. He died in the US airstrike alongside Soleimani.

Abu Mahdi al-Muhandis, the leader of Kataeb Hezbollah, was also killed in the strike against Soleimani, the AP reported.

The US strike on Soleimani came days after the group attacked the US Embassy in Baghdad. This was itself retaliation for US airstrikes in Iraq and Syria that killed 25 members of Kataeb Hezbollah on Sunday.

In other words, even if Iran's own military can't fight the US alone, it could call on its numerous regional partners.

"The strategic consequences can last months, or years," Shapiro, the former US ambassador to Israel, tweeted.

"Time to breathe deeply, prepare seriously, and give our personnel and allies all the support they need."

• Read more:
• Trump tweets predicting Obama would start a war with Iran to get re-elected are coming back to haunt him
• Lawmakers react in strikingly different ways after the US claimed responsibility for an airstrike that killed Iran's top general
• Trump tweeted a photo of the American flag minutes before the Pentagon claimed the US killed Iran's top military general in an airstrike
• How the Trump administration got into a showdown with Iran that could lead to war

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