DAMASCUS, June 7 (Xinhua) -- The U.S.-backed Syrian Democratic Forces (SDF) and allied forces on Wednesday pushed deeper into Syria's northern city of Raqqa, the de facto capital of the Islamic State (IS) group, a day after announcing a broad offensive there, a monitor group reported.
The SDF, which is led by Kurdish YPG group, advanced in several neighborhoods in the western outskirts of Raqqa, and captured the Herakel castle in Sabahiyeh neighborhood of the city, said the Syrian Observatory for Human Rights.
It added that the SDF and other loyal forces reached the western entrance of Raqqa, coupled with battles between the SDF and the IS fighters.
Backed to a few months ago, the Kurdish-led Syrian Democratic Forces (SDF), an alliance of Kurds, Arabs and Assyrians, started an operation dubbed the Euphrates Wreath, against the IS in the countryside of Raqqa.
The operation started with offensives to isolate Raqqa from its countryside and other IS-held areas in eastern Syria.
The SDF, backed by the U.S.-led anti-terror coalition, declared the commencement of the fourth stage of the offensive on Raqqa.
The Observatory said the SDF began the last stage of the offensive to storm the heartland of the IS in Raqqa city on Tuesday morning.
