HASSAN AL-SHAM, Iraq--Iraqi Kurdish fighters are slowly laying the groundwork for a prolonged military offensive against Islamic State forces by reclaiming strategic villages on the northern Iraqi plains as they prepare to serve as the front-line fighters in America's new Middle East conflict.

Backed by a small number of U.S. airstrikes, lightly armed Peshmerga forces routed Islamic State extremists from this deserted village on the rolling plains separating Kurdistan from the militant stronghold in Mosul.

The tentative control of Hassan al-Sham is the latest military victory for Kurdish forces making painstaking progress in reclaiming territory Islamic State militants captured during their summer offensive.

"We've succeeded in stopping them on this front," said Rowsch Nuri Shaways, the former deputy prime minister leading the military campaign. "We're on the offensive and now we control the plains of Mosul."

That battlefield boast overstates the gains Kurdish fighters have made and understates the daunting challenge Iraqi and Kurdish forces face in marching the 30 miles between here and Mosul, which Islamic State fighters have controlled since June.

Kurdish forces and Iraq's national military are ill-equipped for urban street battles with Islamic State fighters. U.S. airstrikes, without better intelligence from the ground, are likely to be less effective in Iraqi cities, where there will be a greater risk of killing civilians. And the international coalition taking shape to defeat Islamic State extremists is in no rush to give Kurdish and Iraqi forces the advanced weapons they want to keep the pressure on their adversaries.

Meanwhile in Syria, Kurdish forces called on Sunday for outside help as the United Nations said 70,000 people had fled into Turkey to escape an Islamic State offensive on regional capital of Ayn al-Arab, a strategic border town.

For now, Kurdish fighters in Iraq are relying on a growing international supply of ammunition, mortars, machine guns and other modest weaponry in the counteroffensive making halting gains.

"Anywhere you see Peshmerga fighters you are safe," a Kurdish soldier said. Minutes later, a mortar fired by unseen Islamic State fighters slammed into the village, sending a dark plume of smoke curling above a black Islamic State flag waving from the roof of an apartment building.

Kurdish forces pushed Islamic State fighters out of Hassan al-Sham, but booby traps the fighters left behind have slowed their efforts to secure the village and allow its residents to return. The ability of retreating Islamic State fighters to fire mortars into the village made it clear that they were much closer than Kurdish officers claimed.

Before retreating from towns and villages they held for weeks, Islamic State forces have booby-trapped faucets, curtains, cabinets and water tanks, soldiers said. They have ignited pools of oil to create smoke cover meant to conceal their positions from American surveillance drones and fighter jets.

In Hassan al-Sham, the fighters blew up three main bridges leading to the village. The main road leading to the bridges is littered with unexploded car bombs, suspicious gas tanks and mysterious canisters that have transformed the paved road into a dangerous car-bomb alley.

Before driving down the road one recent morning, a Kurdish captain leaned over to his aide, kissed his cheek and said farewell. "Goodbye my friend," he told his aide.

"If I have ever done you any wrong, please forgive me," the soldier replied as the pickup truck lurched down a dirt hillside and onto the road. The truck sped past a propane canister placed in the middle of the street and swerved around a pile of cloth set in the center of the pavement.

"There are so many explosives," he said as the pickup truck passed a blue station wagon loaded down by two red barrels he said he believed to be filled with explosives. "We have already removed 25 bombs in this half mile of road."

Ten yards away, a similar red barrel lay in the back of a blue hatchback with a rope running from its front windshield to its rear bumper.

Car bombs have become a common Islamic State weapon, Kurdish forces said.

Earlier that day, Kurdish fighters said they used mortars to destroy an Islamic State truck bomb speeding toward soldiers guarding the town.

"This has already become a dirty war," said Capt. Naquib Ayoub, one of the officers leading the fight to secure Hassan al-Sham.

As they press their counteroffensive, Kurdish leaders are urging the U.S. and its allies to step up their airstrikes, which have so largely been contained to a couple of targets each day.

If the U.S. expects to rely on Peshmerga fighters to lead the battlefield charge, it will have to do more in the coming weeks to give them the weapons, training and airstrikes needed to defeat Islamic State militants, Kurdish officers said.

"The U.S. airstrikes helped a lot," said Mr. Shaways, the Kurdish politician nominated to be finance minister in the new Iraqi government.

"I wish it was a little bit more, but it was enough to boost the morale of our fighters," he said.

Write to Dion Nissenbaum at dion.nissenbaum@wsj.com

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