A US-led international coalition has been in Iraq since 2014 to help local forces fight the Islamic State jihadist group.

Here is a summary of the attacks:

- Rocket attacks -

Repeated mortar and rocket attacks target American interests in Iraq from October 2019.

No one claims responsibility, but Washington blames pro-Iran factions.

A US civilian contractor is killed on December 27 when around 30 rockets are fired at the K1 Iraqi military base in Kirkuk, an oil-rich region north of Baghdad.

Two days later the US bombs a military base in western Iraq where Kataeb Hezbollah, a hardline Iraqi military faction close to Iran, is based. At least 25 fighters are killed.

- US embassy stormed -

Pro-Iran protesters storm the US embassy compound in Baghdad on December 31, 2019, expressing fury over US strikes.

A mob lights fires and chants "Death to America!" before withdrawing a day later.

- US kills commanders -

Tensions between Iran and the US peak in January 2020 following a US drone strike at Baghdad airport that kills Iranian general Qasem Soleimani and top Iraqi paramilitary commander Abu Mahdi al-Muhandis.

In retaliation, Iran launches a volley of missiles at two Iraqi bases housing US and other coalition troops, wounding dozens.

- Deadliest attack -

Two months later, on March 11, a rocket kills two American soldiers and a British soldier, the deadliest rocket attack in years on an Iraqi military base hosting foreign troops.

In response, air strikes kill 26 pro-Iran Iraqi paramilitaries on the Syrian border.

Over the year, dozens more rockets and roadside bombs target Western security, military and diplomatic sites across Iraq -- some of them deadly.

- Truce violations -

After a threat by the US to close down its embassy in Baghdad, Iraqi hardline groups agree to a truce in October 2020.

There are intermittent violations, including a volley of rockets that explodes near the US embassy on December 20.

- Boiling tensions -

In the period since US President Joe Biden took office at the end of January 2021, some 20 bomb or rocket attacks have been launched.

In one attack -- days before Pope Francis visits Iraq in March -- rockets slam into Ain al-Assad base in the western desert, leaving one civilian contractor dead from a heart attack.

On February 15 a wave of rockets hit a military complex inside an airport in Arbil, killing an Iraqi civilian and a foreign contractor working with the US-led troops.

The attack is claimed by a shadowy pro-Iranian group calling itself Awliyaa al-Dam (Guardians of Blood).

There is no immediate claim of responsibility for Wednesday's drone attack, but the same group hails the blast in pro-Tehran channels on the messaging app Telegram.

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