Internally displaced people who fled Raqqa city gather to fill water containers in a camp near Ain Issa, Raqqa Governorate, Syria May 19, 2017. Picture taken May 19, 2017. (REUTERS Photo)

DAMASCUS, June 3 (Xinhua) -- The big battle for dislodging the Islamic State (IS) completely from its de facto capital of Raqqa in northern Syria is near, as Kurdish-led groups, backed by the United States, are making notable gains, a monitor group reported on Saturday.

The Syrian Observatory for Human Rights monitor group said the Raqqa battle is around the corner after the Syrian Democratic Forces (SDF), an alliance of Kurdish, Arab and Assyrian fighters led by the Kurdish People's Protection Units group, captured the towns of Mansura, Hnaideh and al-Baath Dam in Raqqa countryside.

The UK-based watchdog said all three positions were strategic, adding that Mansura is the largest town on the western outskirts of Raqqa.

It said the SDF, backed by the air cover of the U.S.-led anti-terror coalition, are now two km east, three km north, seven km west and 10 km south of Raqqa, namely on the southern bank of the Euphrates River.

The battle in Raqqa started in March when the U.S. carried out airdrops near Tabqa, a prelude to capturing the city and the pivotal dam there.

Even though there is no declared cooperation with the Syrian army, the Syrian government sees the Kurdish groups' fight against IS legitimate.

The government, however, regards the intervention of the U.S.-led coalition as illegitimate, as the state media outlets in Syria release news of civilian deaths by the coalition strikes on daily basis.