The rockets fell in an area where US company Sallyport -- the contractor that maintains F-16 aircraft Iraq has purchased from the US in recent years -- is located, the security source said.

"Initial reports are that there are no US casualties or damages," said Commander Jessica McNulty, Pentagon spokesperson.

No US or coalition troops are assigned at Balad, although US citizen contractors work there, the Pentagon said.

It is the second attack targeting US interests in under 24 hours, after two rockets Sunday targeted an airbase at Baghdad airport housing US-led coalition troops. Sunday's attack did not cause casualties.

There was no immediate claim of responsibility for either attack.

Around 30 rocket or bomb attacks have targeted American interests in Iraq -- including troops, the embassy or Iraqi supply convoys to foreign forces -- since President Joe Biden took office in January.

Two foreign contractors, one Iraqi contractor and eight Iraqi civilians have been killed in the strikes.

Washington routinely blames Iran-linked Iraqi factions for such attacks on its troops and diplomats.

In early April, two rockets hit near Balad, without causing casualties or property damage.