Aircraft from the United States, Australia, France and Britain on Saturday dropped humanitarian supplies to the Iraqi town of Amerli, which has been under siege by "Islamic State" jihadist militants for almost two months, the US Pentagon says.

In a statement, Pentagon press secretary Rear Admiral John Kirby said the airdrop, made at the request of the Iraqi government, had been supported by US airstrikes on the besieging militants.

"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 in the statement.

A later statement from the US Central Command, responsible for the Middle East, said the US supplies had included around 40,000 liters (10,500 gallons) of drinking water and 7,000 pre-packaged meals.

It also said the three airstrikes carried out by the US had destroyed several armed vehicles used by the militants.

Town surrounded

The majority Shiite Turkmen inhabiting Amerli, some 160 km (100 miles) north of Baghdad, have been defending the town amid a bloody offensive by the IS militants. who have captured large swathes of northern Iraq since June.

An initial attack on the town in June was successfully fought off, but the jihadists have surrounded it since mid-July, cutting the inhabitants off from supplies transported by land. Residents say Iraqi military airdrops have not been sufficient to keep the town provisioned with food and water.

Amerli, home to more than 15,000 people, has also been without power for weeks after its power stationed was destroyed.

The IS fighters, who adhere to the Sunni branch of Islam, consider the Shiite Turkmen in the town as apostates.

Iraqi army and Kurdish forces reportedly were closing in on the militants on Saturday in a bid to break the siege.

The US is meanwhile continuing with airstrikes against IS, also known as ISIS (Islamic State in Iraq and Syria), that it began on August 8.

The US Central Command said early on Saturday that fighter aircraft and unmanned drones had carried out five more airstrikes on IS targets near the strategic Mosul dam, bringing to 115 the total number of airstrikes since the US operation began.

tj/se (AP, AFP)