US planes have made humanitarian aid drops to the besieged Iraqi town of Amerli, the Pentagon has said, BBC reported.
Some 15,000 minority Shia Turkmen in Amerli have been surrounded by Islamic State (IS) militants for two months.
The US also carried out air strikes on IS positions. The Iraqi army, Shia militias and Kurdish fighters have been struggling to break the siege.
Aircraft from the UK, Australia, France joined the US in the humanitarian aid drops, said Rear Admiral John Kirby.
Food, water, and medical supplies were delivered.
Rear Adm Kirby said operations would limited in scope and duration, as required to protect civilians trapped in Amerli.
The UN has expressed fears there could be a massacre if IS breaks through defences in the town, which lies in Kurdish-controlled Iraq.
Earlier, the US launched new air strikes on IS near the key Mosul Dam.
In a statement, the US military said an armed vehicle, a fighting position and weapons were destroyed in the raid.
It said the strikes were in support of operations conducted by the Iraqi security forces near the strategic dam in the north of the country.
IS has been accused of atrocities in areas of Iraq and Syria under its control.
The Shia Turkmen are seen as apostates by the IS militants.