About 700 soldiers from the same unit deployed to Kuwait earlier this week when the U.S. Embassy came under attack in Baghdad.

Tensions in the region are running high in the wake of Thursday’s targeted killing of Soleimani, Tehran’s top general and the architect of its interventions across the Middle East.

Iran has vowed “harsh retaliation” for the U.S. airstrike, which was ordered by Trump and carried out near Baghdad International Airport.

Soleimani was the head of Iran’s elite Quds Force and a senior commander, according to a statement from the Pentagon and Defense Secretary Mark Esper, who confirmed U.S. involvement several hours after the attack.

The boost in the number of troops is a sign of the U.S. being concerned that the assassination would spark reprisals by the Iranian government throughout the region.

The United States urged its U.S. citizens to leave Iraq “immediately.” The State Department said the embassy in Baghdad, which was attacked by Iran-backed militiamen and other protesters earlier this week, is closed and all consular services have been suspended.

About 5,200 American troops are based in Iraq, where they mainly train Iraqi forces and help to combat Islamic State militants.

Iran’s Supreme Leader Ayatollah Ali Khamenei warned that a “harsh retaliation is waiting” for the U.S. after the airstrike, calling Soleimani the “international face of resistance.” Khamenei declared three days of public mourning for the general’s death and appointed Maj. Gen. Esmail Ghaani, Soleimani’s deputy, to replace him as head of the elite Quds force.

An unconfirmed number of others were killed when four missiles struck at the airport in Iraq’s capital Thursday, according to multiple news reports and airport security officials.

“General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region,” a statement from the Pentagon said.

Officials said the strike also killed Abu Mahdi al-Muhadis, a high-level militia leader in the Iran-backed Popular Mobilization Forces, according to reports.

News of a big new escalation at Baghdad airport tonight. Two incidents:

1) three Katyusha rockets exploded.

2) A drone strike killed a top Shiite militia leader, the PMF head of protocol Mohammed Ridha, "with his guests."

(Who were his guests??) — Liz Sly (@LizSly) January 2, 2020

Reports say the casualties may also have included 12 Iraqi soldiers.

The PMF militia blamed the United States in the immediate aftermath of the strike.

After the attack, Iran summoned the Swiss charges d’affaires, who represents U.S. interests in Tehran, to protest the killing. Iran’s Foreign Minister Mohammad Javad Zarif called the strike “an act of state terrorism and violation of Iraq’s sovereignty.”

Oil prices surged on news of the attack, and markets were mixed.

U.S. Sen. David Perdue of Georgia tweeted his support for the president’s actions:

.@realDonaldTrump has been clear — when American lives are threatened, he will not hesitate to act with strength.



For decades, Iranian General Soleimani and his terrorist Quds Force have ruthlessly orchestrated the deaths of countless Americans. Now, justice has been served. — David Perdue (@sendavidperdue) January 3, 2020

The Washington Post was the first to report late Thursday that the airstrikes were launched at Trump’s direction.

Earlier reports from Reuters and Al Jazeera News said four missiles struck at or near a facility that housed American and Iraqi counter-terrorism forces, according to Iraqi security forces.

»MORE: Georgia lawmakers divided over U.S. strike that killed Iranian leader

Loud explosions were reported.

A military runway and an airport service road were hit, reports said.

At least one rocket landed near an air cargo hall at the airport, where two SUVs were reportedly hit. Reports said Soleimani was in one of the vehicles in the convoy that was hit as it was leaving the airport.

The civilian area of the airport was reportedly unharmed.

Rockets Strike #Iraq's #BaghdadAirport, #USMilitary Choppers Spotted in Airspace. Three rockets landed on the edge of #Baghdad International Airport , causing explosions but no deaths or injuries, according to local reporters.#IraqiProtests pic.twitter.com/fdEFmkTxpq — Ehab Al Obaidy (@Ehab8Alobaidy) January 2, 2020

Reports said American Apache helicopters immediately took flight from the airport to patrol the skies.

Sirens were blaring in the area, according to witnesses, and early video from the scene showed several civilian vehicles on fire.

Rockets Strike #Iraq's #BaghdadAirport, #USMilitary Choppers Spotted in Airspace. Three rockets landed on the edge of #Baghdad International Airport , causing explosions but no deaths or injuries, according to local reporters.#IraqiProtests pic.twitter.com/TSRPD195PJ — 🇫🇷Amreen Nazanin Rajavi(Amy) (@Amreen__Rizvi) January 2, 2020

The attack came two days after the U.S. Embassy in Baghdad came under attack by Iran-backed militia fighters, who have since retreated.

Tensions in the Mideast region between the United States and Iran have been escalating for months.

In December, a rocket attack at the airport wounded six Iraqi security forces members, marking the 10th attack against U.S. installations or interests in the region in recent weeks.

The attacks have been blamed on Iran-backed militias who appear now to be using more lethal and longer-range rockets.

The U.S. blamed a Dec. 3 attack on the Iran-backed Shia militia group known as Kataib Hezb’Allah.

— Information from The Associated Press was used to supplement this report. This is a developing story. Please return to AJC.com for updates.