About 2,500 IS militants are still in Raqqa, according to the US-led coalition, with about 100,000 people trapped by the fighting in the city.
US-backed Syrian forces have breached the wall at Raqqa’s Old City as they try to retake the city from so-called Islamic State, the US military says.
It says the coalition had helped the advance of the Syrian Democratic Forces (SDF) by firing on two sections of the historic Rafiqa Wall.
The SDF, supported by US-led coalition air strikes, has spent months encircling the city.
IS seized Raqqa in 2014, proclaiming it the capital of a “caliphate”.
The city has been an important hub for the jihadist group’s operations, though as the SDF closed in, key IS officials are believed to have fled from there towards Deir al-Zour province, which is mostly under IS control.
Central Command said air strikes had hit two “small” 25m (80ft) sections of the Rafiqa Wall, which it said “will help preserve” the remaining 2,475m.
It said IS had been planting mines and IEDs [improvised explosive devices] at openings in the wall, through which SDF fighters would have been channelled.
The Old City is highly strategic for the Arab-Kurdish alliance to capture from IS, given its close proximity to the city centre.
Last week, the SDF said its fighters had fully encircled IS in Raqqa.
The US-backed forces have been gradually advancing on the city since November, and launched an offensive to take it on 6 June.
The coalition has said the capture of Raqqa will deliver a “decisive blow” to the jihadist group.
The battle for the city has been brutal for the civilians there.
The UN says that at least 173 were killed in June, and that the actual figure could be far higher, stressing that “civilians must not be sacrificed for the sake of rapid military victories”.
Reports continue to emerge of IS militants preventing civilians from fleeing.
IS is under pressure on multiple fronts, and is on the verge of defeat in what was formerly its biggest stronghold, Mosul in Iraq. It has lost most of the areas it controlled at its height, though it still occupies swathes of territory in Syria and Iraq.
More than 300,000 people have lost their lives in six years of conflict in Syria, which began with protests against President Bashar al-Assad before escalating into a full-scale civil war. Eleven million people have been displaced by the fighting.