President Obama commended Iraqi and Kurdish forces for their teamwork in the retaking the country’s largest dam from Islamic militants on Monday. Obama said the U.S. will continue to deliver humanitarian aid to those displaced by the fighting in the region. (AP)

President Obama said Monday that Iraqi and Kurdish forces, aided by waves of U.S. airstrikes, had recaptured the country’s largest dam, hailing the development as “important progress” against from Islamic State fighters.

While he said other U.S. goals had also been met in Iraq, including stopping a militant surge toward the Kurdish capital of Irbil, Obama declined to set a time frame to limit U.S. military action in the country.

“A lot of it depends on how effectively the Iraqi government comes together,” Obama said.

The president said his primary goal in Iraq is to “make sure we have a viable partner” and a “government formation process that is credible, legitimate and can appeal to Sunnis” and other Iraqi minorities. “We’ve made significant progress on that front, but we’re not there yet,” Obama said.

Iraq’s new prime minister-designate, Haider al-Abadi, has said he will form a new government within the next two weeks. “When we see a credible Iraqi government,” Obama said in remarks in the White House press briefing room, “we are then in a position to engage in planning” for the future.

Asked whether he was concerned about U.S.“mission creep,” Obama said that “if we have effective partners on the ground, mission creep is much less likely.” When U.S. officials “start deciding that we’re the ones that have to do it all ourselves, because of the excellence of our military, that can work for a time, we learned that in Iraq. But it’s not sustainable, it’s not lasting.”

In Iraq, fighting continued on the western bank of the lake at the head of the Mosul Dam on Monday, and government troops were unable to enter the facility because it was booby-trapped by the retreating militants, officials said.

But Iraqi and Kurdish officials claimed that Islamic State fighters were on the run after the offensive launched by Iraqi special forces and Kurdish pesh merga fighters backed by U.S. air support Sunday.

The U.S. military’s Central Command said the airstrikes continued Monday, with a mix of fighter jets, bombers and drones successfully conducting 15 strikes against Islamic State targets near the Mosul Dam. It said the airstrikes damaged or destroyed nine fighting positions, a checkpoint, six armed vehicles, a light armored vehicle, a vehicle-mounted antiaircraft gun and an “emplacement belt” for improvised explosive devices, known as IEDs.

“All aircraft exited the strike areas safely,” the Central Command said in a statement. It said U.S. forces have carried out a total of 68 airstrikes in Iraq since Aug. 8, of which 35 have been in support of Iraqi forces near the Mosul Dam.

Lt. Gen. Qassim Atta, an Iraqi army spokesman, told journalists in Baghdad that the joint operation “fully liberated the dam” and that the troops “hoisted the Iraqi flag over it.”

Brig. Gen. Abdulwahab al-Saidi, an Iraqi special forces commander, said: “The dam is completely under our control. Our soldiers are now relaxing swimming in the lake.”

The claims came a day after Iraqi and Kurdish commanders said they had made unexpectedly swift progress after the operation was launched. They said their forces sliced through a series of villages and reached the dam after a wave of U.S. attacks in which fighter jets, drones and bombers pummeled the extremists’ positions.

It was the biggest offensive since the latest U.S. intervention in Iraq was announced 10 days ago, and it signaled an expansion of what was originally defined as a narrowly focused mission to protect American personnel in Iraq and help fleeing Yazidi villagers trapped on a mountain.

In a letter released Sunday notifying Congress of the action, Obama said the militants’ control of the dam posed a threat to the U.S. Embassy 200 miles away in Baghdad, which could be inundated if the dam were breached.

“The failure of the Mosul Dam could threaten the lives of large numbers of civilians, endanger U.S. personnel and facilities, including the U.S. Embassy in Baghdad, and prevent the Iraqi government from providing critical services to the Iraqi populace,” he wrote.

Obama had signaled in a statement last week that protecting “critical infrastructure” would be part of what officials have described as a limited military intervention. This was, however, the first time Iraqi, Kurdish and U.S. forces had come together to launch a major ground assault.

A week ago, U.S. airstrikes helped clear Islamic State positions, enabling Kurdish fighters to retake two small towns south of the Kurdish capital, Irbil. That marked the Kurds’ first successful effort to recapture territory they had lost to an Islamic State offensive launched two weeks ago.

Kurdish and Iraqi officials said that Sunday’s operation was going better than expected and that the dam would soon be under full government control. “We expect to finish this within hours,” said Helgurd Hikmat, a spokesman for the pesh merga.

A U.S. official, who spoke on the condition of anonymity because of the sensitivity of the situation, also said that the operation had “made significant progress.” But he said that recapturing the dam would take time “because there are a lot of IEDs.”

Late Sunday night, a senior Kurdish official said that Islamic State fighters had abandoned their positions at the dam but that Iraqi and Kurdish forces had refrained from entering the facility because of concerns that it was booby-trapped.

“Everybody is being really careful about their sinister tactics. When they leave their positions, they mine them,” said Hoshyar Zebari, a former Iraqi foreign minister who is working closely with the Kurdish government.

“But we don’t see any resistance whatsoever.”

‘Beat them, beat them’

The Islamic State’s Aug. 7 capture of the Mosul Dam, just hours before Obama announced his decision to send U.S. warplanes back into action in Iraq, was a high point in the group’s campaign to establish a caliphate across the Middle East, putting the militants in control of one of Iraq’s most vital facilities.

Ten days on, it seemed that the intervention was starting to turn the tide.

At the Badriya checkpoint, six miles north of the dam, spirits were high among pesh merga troops blocking the road ahead, citing the danger posed by explosives planted by the retreating militants. Several Islamic State fighters had been captured trying to sneak through Kurdish checkpoints in a bid to escape, said Yunus Said, a volunteer fighter. Others had retreated to the western bank of the Tigris River, he said.

As he spoke, a convoy of SUVs and armored vehicles sped past from the direction of the front line, escorting a pickup in which a bound, blindfolded captive sat.

The soldiers cheered. “Daish,” they shouted, using the Arabic acronym for the Islamic State. “Beat them, beat them.”

Iraq’s elite special forces, which worked closely alongside U.S. Special Forces units before U.S. troops withdrew in 2011, took the lead in the fighting around the dam, while pesh merga troops closed in on the surrounding villages from the north. Saidi, the special forces commander, said the Iraqi air force and SWAT teams also were involved.

Their advance was preceded by the most intense U.S. bombardment yet, with 17 airstrikes Sunday destroying armed vehicles, Humvees, armored personnel carriers and a checkpoint belonging to the militants, according to U.S. Central Command statements. The strikes followed nine in the area the previous day near Irbil and the Mosul Dam.

The assault was the worst setback for the Islamic State since the militants embarked on their stunning rout of the Iraqi army across northern Iraq in June. The group has since continued to expand across Iraq and Syria.

The extremists also came under pressure in Syria on Sunday, with activists in their northern stronghold of Raqqah reporting 23 bombing raids by Syrian government warplanes against Islamic State targets there. The Britain-based Syrian Observatory for Human Rights said there were 84 Syrian airstrikes Sunday, an unusually high number. Of them, 43 were against the Islamic State, signaling a significant escalation of Syrian attacks against the group, which the government had for many months steered away from confronting.

Craig Whitlock contributed to this report. Sly reported from Badriya, Iraq. Morris reported from Baghdad.