Kurdish forces aided by an expanded US air campaign have advanced to within kilometres of Iraq's largest dam, less than two weeks after it was captured by the Islamic State group.
On Sunday, the Kurdish military forces, known as Peshmerga, took control of Tel Skuf, about 15km east of the dam, as well as the towns of Sharafiya and Batnaya, from the Islamic State group, formerly known as ISIL.
Their advance was aided by US air strikes on Islamic State positions. The US central command said it had launched 14 raids on Sunday, to support "Iraqi security forces and Kurdish defence forces ... to combat ISIL" - suggesting its role in northern Iraq had expanded beyond of "supporting humanitarian efforts".
It said the raids had damaged or destroyed 10 armed vehicles, seven Humvees, two armoured personnel carriers and one checkpoint. The US carried out nine air strikes on Saturday.
The White House said late on Sunday that the air strikes were ordered by President Barack Obama because the Islamic State's control of the dam represented a clear threat to Iraqi and US interests.
"These operations are limited in their nature, duration, and scope and are being undertaken in coordination with and at the request of the government of Iraq."
Al Jazeera's Zeina Khodr, in Tel Skuf, said that the Islamic State group still controlled the dam, but US air strikes were helping the Peshmerga retake territory around it.
"US air strikes pushed Islamic State fighters back, but this is not going to be an easy fight," she said. "Now that the group knows it faces a threat from the skies, it is changing tactics on the ground."
In Pictures: The Kurdish frontline in Iraq
Exclusive pictures obtained by Al Jazeera showed destroyed and abandoned Islamic State vehicles along the road leading to the Mosul dam.
Khodr added that Kurdish forces had been slowed down by explosive devices, including homemade bombs and landmines, placed by the Islamic State group.
Al Jazeera's Jane Arraf, reporting from Erbil, the capital of the Kurdish autonomous region in Iraq, said that while the US air attacks were able to hit infrastructure, they were ineffective in dislodging fighters around them.
The Mosul dam is located on the Tigris and provides electricity to much of the region.
The Islamic State invasion of Iraq has led to the worst violence in Iraq since 2006-2007. The group controls large parts of the west and north of Iraq. It has also seized large parts of Syria as it tries to build a caliphate across several countries.
On Saturday, the Syrian Observatory for Human Rights said Islamic State fighters had killed about 700 members of a tribe in eastern Syria.
The monitoring group said the killings took place in several villages home to the Sheitat tribe in Deir Ezzor province. The Observatory said many of the victims were beheaded.