The U.S. assaults hit 10 armed vehicles, seven Humvees, two armored personnel carriers and one checkpoint belonging to Islamic State fighters, the U.S. Central Command said Sunday.
In the past two days, U.S. military forces have conducted 30 airstrikes across Iraq, officials said, with many of them focused around the dam, which militants captured after routing the Kurdish forces 10 days ago. A statement from the National Security Council in Washington on Sunday said the bombings were ordered by President Barack Obama to help the Iraqi forces "retake and establish control over the Mosul Dam."
Obama, the statement added, also officially informed Congress that he had authorized the U.S. airstrikes in Iraq, consistent with the War Powers Resolution.
As of late Sunday, Kurdish government officials said fighting around the dam complex, Iraq's largest, was continuing, despite early reports that the site had been retaken.
"We do not control the entire dam yet," Fuad Hussein, a spokesman for Massoud Barzani, the Iraqi Kurdish president, said in a televised statement.
The air campaign has seemed to check the militants' move against the semiautonomous Kurdish region, an offensive that sent tens of thousands of refugees fleeing for safety and at one point threatened the Kurdish capital, Irbil.
By hammering the militants with warplanes and drones, the Americans have severely curtailed the freedom of movement enjoyed by Islamic State fighters.
It remains to be seen how the Kurdish forces, known as the peshmerga, may fare if the air support is halted, despite Obama's suggestion that it could last months. Having lost significant ground during the Islamic State fighters' sudden advance this month, Kurdish forces have shown that they may not be able to go it alone. The forces pushing into the Mosul Dam area are believed to include the Iraqi Special Forces, making the operation a hybrid of U.S., Kurdish and Iraqi commands.
Kurdish officials acknowledge that the airstrikes have been vital to recent success in halting the militants' onslaught. For their part, peshmerga officials have complained bitterly about inferior arms compared with those used by the Islamic State militants, who have claimed powerful U.S. munitions abandoned on the battlefield by the Iraqi military.
"The aircraft have handicapped" the Islamic State forces. "They cannot move easily," said Hariam Agha, a local commander for the Kurdish forces in Dohuk. "They killed a lot of their fighters."
Since Saturday, 13 militants have been killed in airstrikes and 46 have been wounded, medical officials in the area said.
According to Kurdish officials, Islamic State fighters now appear to be falling back on several fronts, as peshmerga forces approach both the dam and the city of Mosul, which is the capital of Nineveh province. In their wake, they have left mines to slow the progress of Kurdish and Iraqi government forces following in their tracks. The Kurdish advance appeared to have been halted Sunday afternoon, as local fighters and officials said they were awaiting teams to clear the way to the dam.
Still, in Alqosh, at the military base from where the operations to retake the dam originated, there was a decidedly optimistic attitude among the government fighters. Several offered to speak to reporters visiting the area but only if they were not identified because they were not authorized to comment publicly. The soldiers spoke of an imminent victory at the dam as military vehicles passed in and out of the checkpoint area.
Officials also spoke confidently about the re-energized peshmerga forces.
"There is some fighting in different places in the area, but the peshmerga has moved easily forward," said Duraid Hikmat Tobia, a minority affairs adviser to the governor of Nineveh province. "The problem is the mines - they cannot move quickly because they are afraid to hit them."
"Still," he added, "I think tonight or tomorrow the Mosul Dam will be controlled by the peshmerga."
The dam sits on the Tigris River roughly 30 miles from Mosul and is a crucial source of electricity for Mosul as well as a control point for the water supply for a larger area. After the dam fell this month, officials worried that if it failed a 65-foot wave of water could be released over northern Iraq.
But rather than use the dam as a weapon against residents of the region, the militants continued to produce electricity and maintain the site.