BAGHDAD — Boosted by two days of U.S. airstrikes, Iraqi and Kurdish forces today wrested back control of the country’s largest dam from Islamic militants, a military spokesman in Baghdad said as fighting was reported to be underway for the rest of the strategic complex.

Soon after the news broke, the Islamic State group, which two weeks ago captured the Mosul Dam spanning the Tigris River just north of the city of Mosul, denied the claim, insisting it was still in control of the facility.

The retaking of the dam would mark the first major victory for the Iraqi and Kurdish forces battling the Islamic militants since U.S. airstrikes began earlier this month.

It could significantly boost their morale as they try to free territory overrun by the Islamic State in a blitz this summer. Also, the dam and its broader complex hold great strategic value as they supply electricity and water to a large part of the country.

Army spokesman Lt. Gen. Qassim al-Moussawi said the dam itself was secured by Kurdish peshmerga troops and Iraqi security forces on Monday but that the southern side of the complex remains contested and that fierce fighting is underway to free that area.

At least 170 bombs have been dismantled around the dam but many more remain, al-Moussawi added in a televised statement.

Al-Moussawi said the Iraqi and Kurdish forces “hoisted the Iraqi flag over” the dam.

He added that the troops were backed by a joint aerial support but didn’t specify whether there were any U.S. airstrikes in the area of the dam Monday.

Local residents and others in the area could not immediately be contacted to confirm the security forces’ recapture of the dam.

Iraq’s Ministry of Defense said security forces “liberated a large part of the Mosul Dam” with the help of U.S. airstrikes, adding that forces are working to fully free the entire complex. U.S. Central Command would not immediately confirm any involvement.

However, a senior Kurdish commander told The Associated Press that his peshmerga forces had withdrawn from the dam complex on Monday afternoon because it was heavily rigged with explosives. He spoke on condition of anonymity because he was not authorized to talk to media.

In an Internet statement, the Islamic State denied losing control of the dam, dismissing the government claim as “mere propaganda war.” The statement, which could not be independently verified, was posted on a website frequently used by the militants.

The U.S. launched airstrikes against the Islamic State group in Iraq more than a week ago in a bid to halt its advance across the north. The U.S. military said U.S. forces conducted nine strikes Saturday and another 16 on Sunday.

The dam’s seizure by Islamic State militants on Aug. 7 was part of a string of victories by the Sunni radical group as it looks to expand its hold in northern Iraq, driving back Kurdish forces, sending minority communities fleeing and unleashing a wave of violence over a territory straddling the Syria-Iraq border.

The decision to launch airstrikes marked the first direct U.S. military intervention in Iraq since the last American troops withdrew in 2011 and reflected growing international concern about the extremist group.

The White House sent a letter to Congress on Sunday saying that its air campaign in Iraq “is consistent with the president’s directive that the U.S. military protect U.S. personnel and facilities in Iraq, since the failure of the Mosul Dam could threaten the lives of large numbers of civilians and threaten U.S. personnel and facilities — including the U.S. Embassy in Baghdad.”

It also noted that the failure of the dam could “prevent the Iraqi government from providing critical services” to the Iraqi people.

Some 1.5 million people have been displaced by fighting in Iraq since the Islamic State’s rapid advance began in June. The scale of the humanitarian crisis prompted the U.N. to declare its highest level of emergency lasts week.