ISIS fighters had taken up hiding in neighborhoods in the northern portion of the city as well as the dam in an effort to hold onto Tabqa, reported the BBC News.
Dorrian said the SDF fully isolated IS fighters in the Taqba dam, the largest dam in Syria which is a key source of electricity for the region, from the rest of the city.
U.S. Central Command, which oversees U.S. military operations in the Middle East, said approximately 70 Islamic State fighters had conceded to the SDF's terms, which included dismantling bombs surrounding the dam, surrendering their heavy weapons and withdrawing all remaining fighters from Tabqa. The alliance is now working to tighten the noose before a final assault.
There had been fears of a flooding disaster if the explosives were detonated.
The battle for the city of Tabqah and nearby dam began almost two months ago, when American helicopters inserted hundreds of Syrian fighters along with a handful of American special operations forces.
U.S. Air Force Col. John L. Dorrian, U.S. spokesman for the U.S. -led anti-Islamic State global coalition called the Combined Joint Task Force: Operation Inherent Resolve, made the announcement during a webcast press conference on Wednesday.
The decision received immediate pushback from Turkish President Recep Tayyip Erdogan, who regards the YPG as an extension of the Kurdistan Workers' Party, or the PKK, which is considered a terrorist group by both Ankara and Washington.
It lost the strategic airbase, about 45km west of Raqqa, to the SDF last month.
Col Dorrian said the arms include heavy machine guns to be used against ISIL lorry bombs, mortars, small arms and ammunition, as well as armoured vehicles and equipment to detect landmines.
From Erdogan down, there have been numerous statements that the United States needs to effectively choose between Turkey and the YPG.
But Washington's reassurances have failed to assuage Ankara. "They only have different names", Turkish foreign minister Mevlut Cavusoglu said.
A top Syrian Kurdish official said Wednesday, May 10, 2017, that the USA decision to arm Kurdish fighters with heavier weapons will help legitimize the force, which is denounced as a terrorist organization by Turkey.
"The secretary reiterated U.S. commitment to protecting our North Atlantic Treaty Organisation ally", read a State Department statement.
The Turkish leader vowed to table the issue during next week visit to Washington. He has demanded Washington reverse the decision, and said he would take up the issue with Trump.
The YPG militia says the decision is "historic" and a "sign of confidence" in the group, in a statement released Wednesday.