Washington, Jun 28 (IANS): The Pentagon announced that the US military has conducted airstrikes against facilities used by Iran-backed militia groups in the border region between Iraq and Syria.

"The US strikes targeted operational and weapons storage facilities at two locations in Syria and one location in Iraq, both of which lie close to the border between those countries," Pentagon Press Secretary John Kirby said in a statement on Sunday.

The targets were selected because these facilities are utilised by Iran-backed militias that are engaged in unmanned aerial vehicle (UAV) attacks against US personnel and facilities in Iraq, Xinhua news agency quoted the statement as saying.

US media reported that the airstrikes, carried out by F-15 and F-16 fighters, were in response to five militia drone attacks against American forces in Iraq in recent months.

The operation was President Joe Biden's second use of force in the region.

He ordered airstrikes against Iranian-backed militia targets in eastern Syria this February.

The airstrikes came at a delicate time between the US and Iran.

A senior State Department official said on June 23 that the two sides still have serious differences over how to revive the 2015 nuclear deal, after six rounds of indirect negotiations in Austria's capital Vienna since April.