Col. Joseph Scrocca, spokesman in Baghdad for the USA -led coalition fighting ISIS in Syria and Iraq, said in an email exchange Friday that the US -backed Syrian forces have managed to build up their numbers by bringing in additional fighters, along with armored vehicles, using boats on Lake Assad.
A fleet of US helicopters carrying about 500 Syrian fighters and their USA advisors flew into ISIS-held territory March 22 to begin the first major phase of the Raqqa offensive. "The coalition supported this offensive with air movement and logistical support, precision airstrikes, Apache helicopters in close air support, Marine artillery and special operations advice and assistance to SDF leadership".
Retaking the dam would go a long way to isolate Raqqa and is a crucial step ahead of the assault on the city.
Tabqa lies 28 miles west of Raqqa.
While his remarks were short on specifics, Tillerson offered a glimpse of a new US strategy as the militants come under growing pressure.
Eric Pohan said on Tuesday that US military advisers are also on the ground in the Tabqa area to help coordinate the operation.
The offensive has opened up a new front in the campaign to recapture Raqqa, which ISIS branded the capital of its so-called "caliphate" in 2014.
The extent of Kurdish influence in the future running of the city is sensitive both for residents and for North Atlantic Treaty Organisation member Turkey, which has fought its own Kurdish insurgency for three decades and fears growing Kurdish ascendancy just over the border in northern Syria.
Cihan Sheikh Ehmed, the spokeswoman for the Syrian Democratic Forces, said Friday the fighting is ongoing at the entrance of the dam, adding that there are casualties among IS fighters.
Kurdish official Awas Ali, who comes from Raqqa province, said the city council, of which he will be a member, would be unveiled in April.
Although Mosul and Raqqa are the Islamic State group's two most important holdings, their recapture isn't expected to mark their elimination as an worldwide threat.
Also Wednesday, the USA -led coalition against the Islamic State group said it is looking into reports a US -led coalition aircraft may have struck a shelter for the displaced in the village of Mansoura, also held by IS.
The activist-run Raqqa Is Being Slaughtered Silently group said about 50 families had been sheltering at the school in the northern Syrian village of Mansoura and that their fate was still unknown.
Meanwhile, Syria's ambassador to the United Nations Bashar al-Ja'afari accused Washington of "invading my country" in an attempt to beat IS, adding that the operation to liberate Raqqa should be doing in coordination with the Damascus government.
The UN's special envoy for Syria, Staffan de Mistura, has released a statement noting that all parties have arrived for the intra-Syria talks. But the group ultimately fled the city, as it did in the northern Syrian towns of Jarabulus in August and Al-Bab last month, indicating a growing willingness on the part of ISIS commanders to relinquish control of territory in exchange for preserving its ranks in retreat.