The attacks came hours after US Defence Secretary Mark Esper said the US should expect retaliation over the US killing of Iranian military commander Qassem Soleimani in a drone strike in Iraq on Friday. Iran says 80 "America terrorists" were killed in the missile strikes, but US president Donald Trump says "All is Well!

A sprawling air base in western Iraq that hosted President Donald Trump during his first visit to a combat zone as commander in chief was one of two military installations where US troops are stationed that came under ballistic missile attack by Iran early Wednesday.

The attacks came hours after US Defense Secretary Mark Esper said the US should expect retaliation over the US killing of Iranian military commander Qassem Soleimani in a drone strike in Iraq on Friday.

Here’s what we know about the bases and the scale of the attack on Wednesday:

15 missile fired, 80 killed in missile attacks claims Iran

Iranian state television said at least 80 "American terrorists" were killed in attacks involving 15 missiles Tehran launched on US targets in Iraq, adding that none of the missiles were intercepted.

But United States president Donald Trump said in a tweet that an assessment of casualties and damage from the strikes was under way and "All is well!"

Iran's supreme leader said a "slap in the face" was delivered to the US after the attack. "Last night, a slap in the face was delivered," Iran's Supreme leader Ayatollah Ali Khamenei said in a speech broadcast live on state television.

100 other targets in sight, more attacks in case of retaliation: Iran

State TV also said Iran had 100 other targets in the region in its sights if Washington took any retaliatory measures. It also said US helicopters and military equipment were "severely damaged".

Iran's army also renewed a demand for U.S. troops to be withdrawn from the Middle East.

What Is The Strategic Importance of Ain Al-Asad And Irbil Bases?

During the past two years, both Trump and Vice President Mike Pence made unexpected visits to the base, which is in Anbar province and about 135 miles from the Syrian border. At the time of his visit, which he left for on Christmas night in 2018, Trump characterised the journey as harrowing and under the cloak of darkness.

US troops have trained Iraqi troops at the base, located in Anbar province northwest of Baghdad, as part of Washington's bid to build a force that could mount an offensive against Islamic State militants.

Aside from US and Iraqi forces, the air base has also hosted U.S.-led coalition partners Denmark.

Irbil Base: In October, Delta Force commandos stationed at the base started the operation in Syria that led to the death of Abu Bakr al-Baghdadi, the leader of the Islamic State. Eight U.S. helicopters, primarily CH-47 Chinooks, took off from the base, flying low and fast to avoid detection during the mission.

The president, along with Defence Secretary Mark Esper, Pence and Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, watched video of the raid piped into the White House Situation Room from surveillance aircraft orbiting over the battlefield. Pence visited the base in November.

Base Has Hosted Trump:

Over the Christmas holidays in 2018, US President Donald Trump stopped there and made remarks to troops during a surprise visit to Iraq, his first journey to a conflict zone since taking office in January 2017.

Base Has Been Attacked Before

In 2015, the base came under regular harassing mortar fire from Islamic State militants. The same year, the air base was attacked by 25 Islamic State fighters, but the Pentagon said at the time that Iraqi security forces guarding the perimeter killed most of the combatants.

Five rockets landed on the air base last month but did not cause any casualties.

How Many US Troops Are In Iraq?

As of December, there were about 6,000 US troops deployed in Iraq, which is a fraction of the peak number of 150,000 military personnel who served during Operation Iraqi Freedom, which lasted from 2003 to 2011. After Soleimani’s death, the Iraqi parliament voted to expel US troops from the country, which Trump then said would be met with sanctions.