Syrian Kurdish-led forces were clearing mines at the country's largest dam and the nearby town of Tabqa on Thursday, a day after seizing them from Islamic State militants.
The capture of Tabqa, a key step in the advance on Raqqa, the extremist group's de-facto capital, came seven weeks after the launch of the Kurdish-led offensive, backed by the U.S.-led international coalition.
It also came a day after the Trump administration announced it will supply the Kurdish-led Syrian Democratic Forces with heavier weapons, a decision that infuriated Turkey, which views the main Kurdish militia in the group as an extension of an outlawed rebel movement fighting an insurgency in its southeast.
The SDF, which also includes Arab fighters, has captured large swathes of land in northern Syria from IS with the help of U.S.-led airstrikes. But the Kurdish YPG, which forms the backbone of the group, is linked to the Kurdistan Workers' Party, or PKK, which Turkey, the U.S. and other Western nations view as a terrorist group.
Turkish President Recep Tayyip Erdogan called on the U.S. to reverse its decision, saying weapons in the hands of the Kurdish-led forces are a "threat" to his country. Unnerved by the Kurdish advances along the border, Turkey sent troops into Syria last year to help allied Syrian forces battle IS and block the SDF.
The capture of Tabqa sets the stage for an advance on Raqqa, some 25 miles (40 kilometers) to the east.
A spokesman for the coalition, Col. John Dorrian, said that after Tabqa is secured, the Syrian Kurdish-led forces will continue operations to "isolate and seize Raqqa."
Dorrian said 30,000 residents had been displaced since the fight for Tabqa began on March 21, and that the priority was now to protect those who remained.
The media office of the Syrian Democratic Forces said Thursday a special operation was underway to de-mine the dam and the surrounding area.
Concerns were raised earlier this year that the dam could be damaged in the fighting or degraded by lack of maintenance, or that the extremists might sabotage it to flood the surrounding areas.