A US-backed alliance has ousted ISIL jihadists from half of their Syrian bastion Raqqa, a monitor said, as the escalating fighting drove up the civilian death toll.
The Syrian Democratic Forces have been fighting for several months to capture the northern city, which has become infamous as the Syrian heart of ISIL's so-called "caliphate".
The SDF "are now in control of 50 per cent of Raqqa city despite the fierce resistance mounted by ISIL", Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, told AFP on Wednesday.
The SDF assault has been backed by air strikes, special forces advisers, equipment and weapons from the US-led coalition fighting ISIL in Syria and neighbouring Iraq.
On Wednesday, a barrage of US-led air strikes across the city left at least 29 civilians dead, the British-based observatory said.
"At least eight children are among the dead," Mr Abdel Rahman said.
The SDF's Arab and Kurdish fighters first entered Raqqa on June 6, seven months after launching their flagship offensive for the city — called Operation Wrath of the Euphrates.
They have since steadily advanced in a pincer-like motion, closing in on the city centre.
But ISIL has fought back using a slew of car bombs, suicide attacks, weaponised drones and with improvised explosive devices scattered across the city.
The spokeswoman for the SDF's Raqqa operation told AFP that just under half the city was under SDF control.
"Forty-five per cent of Raqqa has been liberated. Our forces are advancing on all sides," Jihan Sheikh Ahmed said late Wednesday.
"The tighter the noose grows around Daesh [ISIL], the more strongly it reacts and the tougher it fights," Ms Ahmed said.
ISIL first seized Raqqa in early 2014, and the city has since become synonymous with the group's most gruesome atrocities.
The jihadists carried out public beheadings there and is also thought to have used Raqqa as a hub for planning attacks overseas.
Tens of thousands of civilians have fled the escalating violence in recent months, but the UN estimates that up to 50,000 people remain trapped inside the city.
Those who have managed to escape have told harrowing tales of dodging sniper fire and mines or paying smugglers to lead them out.
Once ISIL is ousted from Raqqa, a body called the Raqqa Civil Council is expected to run the city's administrative affairs.
But much of Raqqa's infrastructure has been devastated by years under jihadist rule and bombing by various parties in Syria, including the coalition.
Rising civilian toll
With Wednesday's deadly raids, at least 325 civilians, including 51 children, have died in the city since the SDF penetrated Raqqa less than two months ago, according to the observatory.
Another 467 ISIL jihadists and 219 SDF have also been killed in the fighting.
A deputy commander of the international coalition said on Sunday it would have "a great deal more" to do in Syria even after Raqqa is captured.
"Daesh is not defeated with the liberation of Raqqa. The defeat of Daesh was not completed with the liberation of Mosul" in Iraq, British Maj Gen Rupert Jones told reporters, using an Arab acronym for ISIL.
More than 330,000 people have lost their lives in Syria since the country's conflict broke out in March 2011 with anti-government protests.
The widespread popular demonstrations have since evolved into a complex war drawing in world powers on all sides.
On Wednesday, at least 14 civilians were killed when unidentified warplanes bombed territory east of the ISIL-held town of Mayadeen, the Britain-based observatory said.
Five children were among the dead.