The US military on Saturday dropped humanitarian aid to the besieged Iraqi town of Amerli, home to thousands of Shia Turkomen cut off by jihadist rebels from receiving food, water, and medical supplies.

"At the request of the government of Iraq, the United States military today airdropped humanitarian aid to the town of Amerli," said Pentagon press secretary Rear Admiral John Kirby.

"The United States Air Force delivered this aid alongside aircraft from Australia, France and the United Kingdom, who also dropped much needed supplies."

The humanitarian aid was delivered in conjunction with "coordinated airstrikes against nearby ISIL terrorists in order to support this humanitarian assistance operation," the US military officer said, referring to the Islamic State (IS) forces also known as the Islamic State in Iraq and the Levant (ISIL).

"The operations will be limited in their scope and duration as necessary to address this emerging humanitarian crisis and protect the civilians trapped in Amerli," Kirby said.

A later statement from the US Central Command, which covers the middle east, said the US supplies had included around 10,500 gallons of drinking water and 7,000 pre-packaged meals.

The three airstrikes, Centcom said, destroyed "three ISIL Humvees, one ISIL armed vehicle, one ISIL checkpoint and one ISIL tank near Amirli," the statement added.

"The US military will continue to assess the effectiveness of these operations and work with the Department of State, the US Agency for International Development, as well as international partners including the Government of Iraq, the United Nations, and non-government organizations to provide humanitarian assistance in Iraq as needed," Kirby said.

The US military also launched fresh attacks Saturday on IS forces in near Iraq's Mosul dam, deploying fighter aircraft and drones to carry out the airstrikes, the Pentagon said earlier on Saturday.