US-backed forces captured a new district from jihadists in Syria's Raqa but struggled to hold their positions against suicide car bombers, a fighter in the city and a monitor said.

The Syrian Democratic Forces (SDF), an alliance of Kurdish and Arab fighters, seized the eastern Batani district from the Islamic State group on Thursday.

"Late Thursday, they began an offensive on neighbouring Al-Rumeilah," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.

Clashes were raging on Friday as IS deployed its typical defensive tactics: weaponised drones, snipers, and improvised explosive devices, Abdel Rahman told AFP.

An SDF fighter near Al-Rumeilah told AFP on Thursday that suicide attackers were using explosives-laden vehicles to hold back the SDF.

"They're sending booby-trapped cars towards our positions, and as they fall back, they're laying mines," said the 30-year-old fighter, who identified himself as Abu.

Civilians "can't move. They can't leave during the day because of snipers."

Abu said his unit had managed to open up an escape route for residents of Al-Rumeilah, like 56-year-old Abdel Halim Ulaywi.  

"Ten days ago, a strike hit our home and we ran inside quickly. My sister was hit in the stomach and started bleeding. She stayed alive for six days and then she died," Ulaywi said.

He had tried to escape several times "but IS kept forcing us back," he told AFP.

According to Abdel Rahman, IS has slowed down the SDF's push in other parts of Raqa, including the Old City. 

"The SDF is struggling to hold newly seized positions in the Old City because of intense sniping and escalating attacks by drones carrying bombs," he said.

IS captured Raqa in early 2014, transforming the northern Syrian city into the scene of gruesome atrocities like public beheadings. 

The SDF, backed by US-led coalition air strikes, spent months encircling the city before finally breaking into it on June 6. 

The militia has since captured around 30 percent of the city, according to the British-based Observatory. 

Source: AFP