UPDATE 1615 GMT: Iraqi troops, Kurdish peshmerga, and Shia militias have now broken the siege of Amerli and entered the town where 15,000 residents were at risk from shortages of food, water, and medical supplies:

The US has renewed its airstrikes on Islamic State positions in northern Iraq, supporting operations to relieve the besieged town of Amerli and attacking near the Mosul Dam.

Alongside planes from Britain, France, and Australia, US aircraft also dropped humanitarian aid into Amerli, where 15,000 people have been surrounded for more than two months when the Islamic State captured more than 30 nearby villages and positions.

See Iraq Feature: Amerli — The Town Holding Out Against the Islamic State and Starvation

Rear Admiral John Kirby, the Pentagon Press Secretary, said:

At the request of the government of Iraq, the United States military today airdropped humanitarian aid to the town of Amerli, home to thousands of Shia Turkmen who have been cut off from receiving food, water, and medical supplies….

In conjunction with this airdrop, U.S. aircraft conducted coordinated air strikes against nearby ISIL (Islamic State) terrorists in order to support this humanitarian assistance operation.

On Saturday, Iraqi and Kurdish forces moved towards Amerli from four directions in an effort to break the siege. An Iraqi officer said progress was slow because roads were mined; however, he said his force was about 15 km (9 miles) from the town, while those approaching from the north were only 3 km (2 miles) away.

The major said he had counted the corpses of more than 40 Islamic State fighters from airstrikes on the road between Udhaim and the village of Injana.

The US Central Command added that five airstrikes near the Mosul Dam had destroyed an Islamic State position, an armed vehicle, and weapons, and significantly damaged an Islamic State building.

The American aerial attacks, initially justified to support humanitarian operations after the jihadist advance in northwest Iraq, have been supporting a Kurdish counter-offensive for more than three weeks. Almost two weeks ago, Kurdish peshmerga retook the Mosul Dam, Iraq’s largest, from its 12-day occupation by the Islamic State.

The US has also used the strikes to check any Islamic State advance on the Iraqi Kurdistan capital of Erbil.

Central Command said it has conducted a total of 115 airstrikes since August 8.