The attack on the sprawling Ain al-Assad base in Iraq's western desert is the fourth time in less than three weeks that rockets hit a Western installation in the country.

Ain al-Assad hosts both Iraqi forces and troops from the US-led coalition helping fight remnants of the Islamic State group -- as well as the unmanned drones they use to surveil jihadist sleeper cells.

Coalition spokesman Colonel Wayne Marotto confirmed that 10 rockets hit the base at 7:20 am (0420 GMT), but did not provide details on any casualties.

Iraqi security forces said they had found the platform from which 10 "Grad-type rockets" hit the Ain al-Assad base, saying there were "no notable casualties".

Western security sources told AFP the rockets were Iranian-made Arash models, which are 122mm artillery rockets and heavier than those seen in similar attacks.

Dozens of rocket attacks and roadside bombs targeted Western security, military and diplomatic sites in Iraq in 2020, with Iraqi and Western officials blaming hardline pro-Iran factions.

They came to a near-complete halt in October following a truce with the hardliners, but they have resumed at a quickening pace over the past three weeks.

In mid-February, rockets targeted US-led coalition troops in the Kurdish regional capital Arbil, killing two people.

Days later, more rockets hit a US military contracting company working north of the capital and the US embassy in Baghdad.

- Boiling tensions -

The US responded on February 26 with a US air strike on Kataeb Hezbollah, an Iranian-backed Iraqi paramilitary force stationed along the Iraqi-Syrian border.

Washington says it struck on the Syrian side of the border but Kataeb said one of its fighters who was killed in the bombardment was protecting "Iraqi territory".

Analysts have pointed to both domestic and international reasons for the sudden rise in tensions.

Hardline Iraqi groups have an interest in ramping up the pressure on Prime Minister Mustafa al-Kadhemi following his pledges to rein in rogue militias.

They may also carry a message from Tehran to Washington, which under US President Joe Biden is offering to revive the Iran nuclear deal which his predecessor Donald Trump abandoned in 2018.

Iran is demanding the US lift sanctions immediately, while the US wants Iran to move first by returning to previous nuclear commitments.

Despite the escalation in recent weeks, Pope Francis appears determined to go ahead on Friday with the first-ever papal visit to Iraq.

While he is not set to be in the country's west, he will spend time in Baghdad and Arbil, both hit by rocket attacks last month.

Iraq is simultaneously gripped by a second wave of the coronavirus, which is seeing more than 4,500 new cases a day in the country of 40 million.

To stem the spread and control the crowds during the Pope's visit, Iraq is set to extend its weekend lockdowns to include the entirety of the papal visit from March 5-8.