A week ago, there was just a single house where U.S. soldiers had hoisted an American flag on a hill not far from a tense front line in Syria.

On Wednesday, there was a growing fortified position with a perimeter of large sand barriers and barbed wire, a new watch tower and a half-dozen armored vehicles.

Even as U.S. President Donald Trump spoke of pulling out of Syria “very soon,” an Associated Press team saw American forces setting up front-line positions outside the strategic northern town of Manbij, west of the Euphrates River.

The U.S. is building two military bases in the region of Manbij west of the Euphrates River, which is under the control of the Kurdish People’s Defense Unit (YPG), reports the Turkish news agency Anadolu.

Trump's White House said on Wednesday America's military mission to eradicate Islamic State in Syria "is coming to a rapid end."

"We will continue to consult with our allies and friends regarding future plans," the White House press office said in a statement.

The area is the scene of a tense standoff. U.S.-backed Kurdish-led forces who hold Manbij are facing off against Turkish-backed Syrian fighters.

Turkey has vowed to retake Manbij and other Kurdish-held territory along the Syrian-Turkish border; the U.S. troops stationed here are a key reason why they are holding back.

The U.S.-led coalition in Syria said last week that there were no U.S. bases in the area and that U.S. patrols were not fixed in one place.

In response to an AP query, Pentagon spokesman Eric Pahon said the coalition cannot discuss specific movements and locations of forces in Syria.

He said that commanders are delegated the authority and the responsibility to position people and resources needed to accomplish the mission and to protect themselves.

“Occasional modifications to force size would therefore be normal,” Pahon said in an email.

The AP team, which was escorted by Kurdish fighters, saw that the new U.S. outpost was a work in progress.

A half-dozen armored vehicles sat on opposite sides of the outpost, each with a soldier on watch. A couple of soldiers at one end plowed the ground to lay sandbags, while another group worked out at the other end. Inside an observation post atop a roof, a soldier scanned the horizon through binoculars. A forklift was parked near some wooden planks, indicating more work remains to be done.

The outpost was clearly visible from a main road, with civilians and a mosque nearby.

A front-line commander in Manbij and a member of the Manbij Military Council, the joint Kurdish-Arab body leading the U.S.-allied forces here, said the post went up a week ago.

“We are 1 kilometer from (the village of) Datat, the front line. There is a new U.S. position constructed here. It has been here for seven or eight days here,” said the commander, who spoke on condition of anonymity in line with the Kurdish-led force’s regulations but goes by the nom de guerre of Ali Manbij.

Previously, the U.S. forces only patrolled the front line and kept one position near Manbij, but now more forces are expected at the new post, the local commander said.

“Before, it was only patrols. Now it is better,” he said. “It is to protect the area and to ensure that there is no attack from Turkey or from the mercenaries in the area.”

A Kurdish official on the site said more such posts are expected to be built along the more than 50-kilometer front line with Turkey-backed Syrian fighters.

Trump and his national security team are having a contentious debate about the U.S. role in Syria, where the coalition has been fighting the Islamic State militant group since 2014. About 2,000 U.S. troops are in Syria. Manbij was liberated from ISIS control in 2016 after fierce battles that lasted nearly three months.

Trump told reporters Tuesday that he expects to decide “very quickly” whether to remove the forces, saying their primary mission was to defeat ISIS.

“We’ve almost completed that task,” he said.

The White House said Wednesday the U.S. military mission in Syria was coming to “a rapid end” but offered no firm timeline for withdrawal.

With allies anxious about a hasty U.S. withdrawal, the Trump administration said it would stay in Syria to finish the job of defeating IS and was committed to eliminating the militants’ “small” presence that “our forces have not already eradicated.”

“We will continue to consult with our allies and friends regarding future plans,” White House press secretary Sarah Sanders said in a brief written statement. “We expect countries in the region and beyond, plus the United Nations, to work toward peace and ensure” that ISIS never comes back.

The head of the U.S.-backed Manbij Military Council noted the conflicting statements from Washington but said the U.S. officials in Syria, including senior military commanders, have said “they will stay in Manbij.”

The council official, who spoke on condition of being identified only by his nom de guerre Mohammed Abu Adel in line with regulations, said other coalition forces may take over if the U.S. decides to withdraw.

“The statements from U.S. President Trump may cause concern on the street level. He is a president, after all, saying these things. This causes concern in the street but we hope they stay here,” the official told AP. “These statements — we don’t know their meaning exactly, but the forces are currently there on the front line.”