Syrian Democratic Forces (SDF) fighters walk on the rubble of a damaged street in the Raqqa's al-Sanaa industrial neighbourhood, Syria June 14, 2017. Picture taken June 14, 2017. (REUTERS photo)

DAMASCUS, June 15 (Xinhua) -- The U.S.-backed Syrian Democratic Forces (SDF) have taken control of 30 percent of Syria's northern city of Raqqa, the de-facto capital of the Islamic State (IS) group, a monitor group reported on Thursday.

Intense battles have raged in Raqqa between the SDF and IS, following the collapse of a deal between the leaders of the local tribesmen and the IS, which was designed for allowing the IS fighters to leave Raqqa with their light weapons, said the Syrian Observatory for Human Rights.

The London-based watchdog group said the deal to evacuate IS fighters from Raqqa collapsed due to the rejection of a group of IS fighters.

Activists said that 4,000 fighters of the tribesmen are fighting with the SDF against IS.

A week into the battles for capturing Raqqa from IS, the SDF captured several neighborhoods in the eastern and western parts of Raqqa.

Activists said the SDF and allied fighters are fighting to lay a siege on Raqqa from its southern rim.

The recent battles are being fought south of Raqqa toward the New Raqqa Bridge and Cornish Street, as part of the SDF plan to besiege Raqqa from its southern gates, activists said.

As for the Syrian army, the Observatory said the Syrian government forces are advancing against the IS militants in the western countryside of Raqqa.

The Syrian forces captured on Wednesday the Sufyan oilfield west of Raqqa, closing to the areas under the SDF control in Raqqa from the direction of the Tabqa city.

The aim of the Syrian army battles in Raqqa countryside is to isolate the IS militants in the southern countryside of Aleppo province as a prelude to dislodge them out of that province.

A source told Xinhua that there is no direct coordination between the SDF and the Syrian army, adding that there seems to be a plan between the U.S. and Russia regarding the roles of each force in the battle for Raqqa.

The U.S. has been backing the SDF, which is a group of Kurd, Arab and Assyrian fighters led by the Kurdish YPG, which resulted in the falling of civilian casualties in Raqqa.

A day earlier, the UN Commission of Inquiry said that intensified coalition air strikes have killed at least 300 civilians in Raqqa since March.

The SDF announced their campaign to liberate Raqqa under the title of "Euphrates Wrath" in November last year, and declared their fourth stage of the attack to storm the Raqqa city last Tuesday, after months of battles at outskirts and countryside of the city.