President Joe Biden okays air strike against a structure belonging to what the US says were Iran-backed militia.

FILE PHOTO: A pair of US Air Force F-15E Strike Eagles fly over northern Iraq after conducting air strikes in Syria, in this file photo taken early in the morning of September 23, 2014.
FILE PHOTO: A pair of US Air Force F-15E Strike Eagles fly over northern Iraq after conducting air strikes in Syria, in this file photo taken early in the morning of September 23, 2014. (Reuters)

US air strikes against Iran-backed militias in eastern Syria have killed at least one fighter and wounded several others in what US officials said was a calibrated response to rocket attacks against American personnel in Iraq.

The attacks, which took place early on Friday Middle Eastern time, were deliberately limited in scope and designed to show that President Joe Biden's administration will act tough but wants to avoid a major regional escalation, US officials said.

"At President Biden's direction, US military forces earlier this [Thursday] evening conducted airstrikes against infrastructure utilised by Iranian-backed militant groups in eastern Syria," said spokesman John Kirby in a statement on Friday.

"These strikes were authorised in response to recent attacks against American and Coalition personnel in Iraq, and to ongoing threats to those personnel," he said.

An Iraqi militia official close to Iran said Friday's strikes killed at least one fighter and wounded four more, hitting positions of the powerful Kataib Hezbollah paramilitary group along the border.

Local sources and one medical source in eastern Syria told Reuters at least 17 people had been killed, but gave no further details. That toll could not be confirmed.

While the bombing could be the first retaliatory moves by the United States following last week's attacks, Thursday's strike appeared to be limited in scope.

Also a decision to strike only in Syria and not in Iraq would give the Iraqi government some breathing room as it carries out its own investigation of a February 15 attack that wounded Americans.

READ MORE: Deadly rocket attack hits US base in northern Iraq

US military strikes

Retaliatory US military strikes have occurred a number of times in the past few years.

The rocket attacks against US positions in Iraq were carried out as Washington and Tehran are looking for a way to return to the 2015 nuclear deal abandoned by former US president Donald Trump.

In the February 15 attack, rockets hit the US military base housed at Erbil International Airport in the Kurdish-run region killing one non-American contractor and injuring a number of American contractors and a US service member. 

Another salvo struck a base hosting US forces north of Baghdad days later hurting at least one contractor.

READ MORE: The longer the US drags its feet on Iran, the tougher talks will get

Source: Reuters